empty beds , wasted dollars was the strategic communications and advocacy strategy developed and executed by edward borges to support new york state office of children and family services commissioner gladys carrion 's transformation of new york 's juvenile justice system from a failed , punitive , correctional model to an evidence-based program to improve outcomes for children and make communities safer , despite formidable opposition from upstate republican legislators in whose districts the majority of juvenile jails were located and the employees who worked in these facilities .

empty beds , wasted dollars campaign generated more than 300 newspaper , magazine , television , radio and online story and op-ed placements and 30 editorials in fewer than three years .

it is widely-credited with creating the political capital needed to close more than half the state 's juvenile jails where children in custody had been maltreated by state employees and where an emotionally disturbed 15-year-old boy was killed in 2006 , when two state workers sat on him until he stopped breathing .

the success of this campaign provided carrión the clout to advance reform of the state 's child welfare and child care systems and improve overall child well-being across new york .

empty beds , wasted dollars

the oversupply - estimated at 8 , 700 beds - has wasted hundreds of millions of dollars because public and private health - care funds help pay for their upkeep , whether they are occupied or empty , the state officials said .
with the headline : about 25 % of beds in hospitals in city are empty , state reports .
the new prisons in tuba city and kayenta , ariz . , have court space and peacemaking rooms , but the space for prisoners grew to 132 beds from a planned 48 beds , and 80 beds from a planned 32 beds , respectively .
jjp’s “empty beds , wasted dollars” campaign , funded by the jeht foundation , focused on the plan’s good fiscal sense : the facilities are either mostly or completely empty , and each empty bed costs the state $ 140 , 000 to $ 200 , 000 per year . ocfs forecasted $ 16 million in annual savings to taxpayers . with state revenue shortfalls looming , the financial argument for closing the prisons was persuasive . jjp was successful in garnering media attention statewide , including editorials in the new york times and albany times union questioning the logic of keeping underutilized facilities open at the expense of taxpayers when more effective & # 8212and less costly & # 8212alternatives are available .
if the new system is adopted in new york next year , as state health officials say is likely , hospital stays for all patients will become even shorter , thus adding more empty beds to the excess .
that’s just one example of how private prison companies keep the dollars rolling in , whether crime is rising or waning . not surprisingly , in the public interest’s report calls on local and state governments to refuse to include occupancy requirements and even ban such requirements with new legislation . “with governmental priorities pulling public funds in so many different directions , it makes no financial sense for taxpayers to fund empty prison beds , ” the report says .
according to the health systems agency , the cost of replacing 1 , 000 hospital beds would be nearly $ 500 million . it estimated that it would cost $ 2 billion to operate them over the next 25 years , whether empty or occupied .
state officials said the excess persisted despite the fact that 6 , 000 hospital beds had been eliminated in the city since 1972 , when the city had 112 hospitals with 42 , 984 beds .
rebuilding hospitals with underused beds , as proposed by several major institutions , would waste billions more , they said .
according to state officials , hospital stays for surgical patients are being shortened and more surgery is being performed on an outpatient basis . another factor is the shift of surgery from hospital operating rooms to outpatient surgical clinics . these outpatient trends , combined with the increasing use of second surgical opinions , state health officials say , are leaving rising numbers of surgical beds empty .
you might be wondering : what happens when crime drops and prison populations dwindle in states that agreed to keep their private prisons 80 percent or 90 percent full ? consider colorado . the state’s crime rate has sunk by a third in the past decade , and since 2009 , five state - run prisons have shuttered because they weren’t needed . many more prison beds remain empty in other state facilities . yet the state chose not to fill those beds because democratic gov . john hickenlooper and cca cut a deal to instead send 3 , 330 prisoners to cca’s three colorado prisons . colorado taxpayers foot the bill for leaving those state - run prisons underused . in march , christie donner , executive director of the colorado criminal justice reform coalition , estimated that the state wasted at least $ 2 million in taxpayer money using cca’s prisons instead of its own .
two brand new tribal jails built by the navajo nation in arizona and paid for by the federal government are sitting almost empty because they’re more than twice as large as planned — and now there’s not enough money to run them .
about a quarter of the 36 , 479 beds in new york city ' s general hospitals are unused and unnecessary , according to state health department officials .
the number of unnecessary beds has increased dramatically over the last few months , brian hendricks , deputy director of the state office of health systems management , said .
given these trends , the state health commissioner , dr . david axelrod , said he did not want to approve the rebuilding of hospitals with unnecessary surgical beds . the issue is important , health officials said , because new york hospitals have proposed $ 4 billion in rebuilding and they want to insure that unnecessary beds are not included in any rebuilding .
the tribe , like many others , has long struggled with tiny , run - down jails that need replacing and a shortage of beds . modernizing its correctional system has been a high priority .
the current excess is nearly seven times the 1 , 300 unnecessary beds reported by state and federal health planning officials two years ago after a one - year state freeze on all major hospital construction .
when the state last estimated the oversupply of beds at 1 , 300 , dr . axelrod said he would try to cut by as much as half the $ 2 billion in hospital rebuilding proposed in manhattan .
hospital officials regard any decision on the issue of excess beds as critical because health care is the city ' s third largest industry , accounting for $ 18 billion a year , surpassed only by government and retailing .
the state has contended that there are too many hospital beds in the city , primarily in the big teaching hospitals in manhattan and in the municipal hospital system , cutting across poor and rich neighborhoods . in recent months , the problem has increased dramatically , the state officials said .
now , however , with the state projecting a much larger surplus of beds , mr . hendricks said the state would take ' ' a much more aggressive position ' ' in approving new construction , particularly in manhattan , where several large teaching hospitals have proposed the major share of rebuilding .
by means of a highly technical formula that is regularly disputed by the hospitals , the state health department periodically measures the volume of services provided by each hospital and then calculates how many beds are needed to deliver them . the count by the state covers only public and private teaching and community hospitals and not long - term care , psychiatric or veterans administration hospitals .
state health officials attributed much of the excess of beds to a sharp decrease in hospital surgery and to several trends and regulatory changes involving strict federal review procedures that have affected new york hospitals in recent months . hospital spokesmen say occupancy rates for hospitals , particularly for surgery , have declined . but they say the drop is not nearly as deep as reported by the state .
presbyterian hospital and mount sinai medical center have already received approval of their rebuilding plans , totaling nearly $ 1 billion . state health officials said new york hospital and st . luke ' s - roosevelt hospital center , with an estimated total of $ 800 million in proposed rebuilding and a total of 2 , 757 beds , would face tougher restrictions than those imposed on presbyterian and mount sinai hospitals .
occupancy requirements , as it turns out , are common practice within the private prison industry . a new report by in the public interest , an anti - privatization group , reviewed 62 contracts for private prisons operating around the country at the local and state level . in the public interest found that 41 of those contracts included occupancy requirements mandating that local or state government keep those facilities between 80 and 100 percent full . in other words , whether crime is rising or falling , the state must keep those beds full . ( the report was funded by grants from the open society institute and public welfare , according to a spokesman . )
corrections supervisor lt . robbin preston gives a tour of the new adult detention center in tuba city , ariz . navajo nation officials say the tribe lacks funding to fully staff the jail ( ap / felicia fonseca )
that’s what the justice department’s watchdog found in a report released wednesday that shows how $ 70 . 3 million in economic stimulus grants turned a crucial need in indian country to incarcerate and rehabilitate adult offenders into two white elephants .
the audit by inspector general michael e . horowitz says about half of that money went out the door improperly , more than $ 32 million of it on the jails’ “excessive” and “larger than planned” size . the construction lacked proper oversight not just by the navajo nation but the justice department itself , the watchdog found .
the office that gave the grants to the navajo tribe was aware of the projects’ creeping scope but didn’t take “sufficient action” to prevent them from moving forward .
“the excessive size of both facilities creates increased costs for operations and maintenance staff , ” auditors wrote — costs that are mostly funded by the interior department’s bureau of indian affairs .
right now , that office can pay for just 40 percent of the tribal corrections officers needed to staff the new , larger - than - planned jails .
as a result , “there is an increased risk that the [ facilities ] will not become fully operational due to a lack of funding , ” says the report , which also found sloppy accounting and financial controls over the construction and inadequate vetting of the builders .
the sprawling navajo nation , located in parts of arizona , utah and new mexico , is the largest and most populous indian reservation , with 250 , 000 people on more than 27 , 000 square miles .
visitors walk up to the a new adult detention facility in tuba city , ariz . , navajo nation officials say the tribe lacks funding to fully staff the jail . ( ap / felicia fonseca )
the increases seem at odds with crime rates on the reservation : the average monthly jail occupancy for tuba city from 2008 through 2014 was between 14 and 22 inmates , with a high of 49 , auditors found . and the average occupancy for kayenta during the same period was between 7 and 11 inmates , with a high of 24 .
the inspector general says the justice department should recoup the extra $ 32 million in construction costs from the navajo division of public safety , which received the grants . but justice department officials and the tribe said the changes to planned bed space were carefully vetted with planning studies and documentation .
but the watchdog said new designs for the kayenta jail were done more than two years after the grants were awarded and way after construction had started .
the justice department “does not believe these facilities are excessive , ” ralph martin , director of the office of audit , assessment , and management for the office of justice programs wrote in response to a draft of the report .
martin acknowledged that “in hindsight , ” the office that made the grants “recognizes that there appears to be some discrepancy with the recommended size for the facilities in relation to the [ plan completed in 2007 ] . ” but he said “no formal scope change” was required by the terms of the project , which was desperately needed by the tribe to alleviate years of poor jail conditions .
the navajo nation , in a similar response , wrote that the crime statistics cited by the inspector general are misleading : the tribe’s judges had to stop prosecuting certain crimes because there was no safe space for offenders to be incarcerated . and the master plan was intended only as a “vision” that could be modified .
the justice department and indian tribes share jurisdiction in criminal justice matters , with the federal government prosecuting serious crimes and tribal governments handling smaller offenses . construction of correctional centers is generally funded by federal grants , and the indian affairs bureau covers most staffing costs .
the tuba city corrections center opened in 2013 , but today it is 82 percent vacant because the tribe does not have the money to pay corrections officers . the kayenta jail is completed but still not opened .
the indian affairs bureau told auditors that they can pay for just 25 of the 63 full - time correction officers needed to staff the tuba city jail and 20 of the 51 officers needed at kayenta .
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in february , shortly after new york’s office of children and family services ( ocfs ) announced its plan to close six juvenile facilities , the ca’s juvenile justice project ( jjp ) launched a strategic campaign to educate the public about the closures and urge policymakers to support the agency’s plan . correctly predicting backlash from upstate legislators who wanted to keep the facilities open for the jobs they provided in their districts , the ca sought to prevent the legislature from restoring funding for the prisons in the state budget .
but it was never just about the money the state would save . the closures are part of a broader paradigm shift in the agency’s outlook on juvenile justice . ocfs commissioner gladys carrión explained : “instead of continuing to pour money into this broken system and confining these children to facilities hundreds of miles from their homes , ocfs has aggressively been moving toward more community based alternatives to incarceration where these children can maintain and strengthen connections with their families and the significant adults in their lives . ”
the analysis that the juvenile justice system is in need of overhauling , and that investing in community alternatives is the first step , echoes reforms for which the correctional association and others have long advocated . a year and a half ago , before new leadership at the agency , few would have expected ofcs to take such a stance . despite soaring recidivism rates and its disproportionate confinement of youth of color , the old ocfs was loath to acknowledge the need for change . its administrators certainly had little interest in hearing from reform - minded groups like the ca .
but by january , ocfs’ announcement came as no surprise to the ca , which over the past year has been working closely with agency officials on a range of important juvenile justice reform issues . as the ca’s legislative mandate to monitor and report on state prisons does not extend to juvenile prisons , this degree of cooperation provides access to what has essentially been a closed system . shutting down underutilized facilities was an important step in the agency’s ambitious redesign , and the ca fully supported the plan .
a few days before the state budget deadline , the ca brought over 50 young people and other advocates to albany to speak directly with policymakers about the issue . during the subsequent budget negotiations , the closures became a bargaining chip between the assembly and senate , and after much wrangling , governor paterson and the legislature restored funding for two of the facilities . while the ca strongly supported closing all six facilities , the closure of four is nevertheless an advance for advocates , for youth involved in the juvenile justice system , and for an agency attempting to remake itself .
the budget battle now over , the ca will turn to supporting the agency’s pledge to reinvest funds in community - based alternative to incarceration programs . with carrión and ocfs still committed to improving outcomes for troubled youth and willing to collaborate with advocates , there is good reason to remain optimistic .
correctional association of new york releases “solitary at southport : a 2017 report based upon the correctional assn . ’s visits , data analysis , & first - hand accounts of the torture of solitary confinement from one of new york’s supermax prisons”
new york , ny ( december 13 , 2017 ) : today the correctional assn . of ny ( ca ) , founded in 1844 and one of the oldest prison watchdog organizations in the country , released a 92 - page report providing graphic first - hand depictions of physical , mental , and emotional abuse as a result of days , weeks , and often years of being caged in solitary confinement for 23 to 24 hours a day . read more
southport correctional facility is one of two super - maximum security prisons in the state that places an emphasis on solitary confinement . a new report looking at the facility’s practices is highlighting the negative impact solitary confinement can have on a human . so advocates are making a renewed push for the halt act . joining us to talk [ . . . ] read more
“the isolation itself is torture . mentally and emotionally , it breaks you down . spiritually it strips you . the way it is built is to break you down as a person and push your family away . ” from “solitary at southport” solitary confinement is torture . new york state subjects people to solitary confinement and other forms of isolation [ . . . ] read more
attica correctional facility , a 2 , 000 - bed maximum security prison in western new york , continues to operate as a symbolic and real epicenter of state violence and abuse of incarcerated persons in the department of corrections and community supervision ( doccs ) state prison system 43 years after the 1971 prison uprising and violent suppression by state authorities . the [ . . . ] read more
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eddie borges is irecting documentary about mexican and puerto rican childhood poverty united states . h
campaign to support the transformation of new york ' s juvenile justice system . this included closing more than half of the state ' s juvenile jails where black and latino children were maltreated and a child was killed .
borges is a motion picture and film producer & director at searching for los ríos and a founder at childpoverty . he was also the following : a us consultant at the rockefeller family fund and
director of communications and external affairs at times square alliance . tonite he will be discussing his latest projects .
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' ' there has been a decline , ' ' said kenneth e . raske , the president of the greater new york hospital association , which represents the city ' s private , nonprofit hospitals . ' ' but we do not think the dip is anywhere as sharp as reported by the state . ' '
but mr . hendricks of the state ' s health systems office disagreed . ' ' what we have is a dramatic decline in patient census , ' ' he said .
anthony l . watson , the executive director of the new york city health systems agency , a federally financed health planning group , said , ' ' the decline is so sharp that there is a likelihood that some hospitals may not survive the bed reductions that must be made . ' ' the agency is empowered by congress to disapprove any hospital construction it regards as unnecessary .
the state officials also cited an increasing awareness by hospitals that they would not be paid for any unnecessary hospital care under the medicare program for the elderly in a tough new review program that began this winter . if review inspectors decide surgery is unnecessary , the hospital forfeits any payment .
another change that is already causing a reaction in many hospitals is new york ' s anticipated adoption next year of the same hospital bill payment system that was adopted by medicare in 1983 in most other states . new york was excluded because it was conducting a federally approved experimental payment system of its own . that system is scheduled to end dec . 31 .
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under the medicare system , the hospital gets a flat - rate payment , no matter how long the patient is hospitalized . the new flat - rate system was designed to reduce the financial incentive to hospitalize medicare patients longer than necessary , just to realize more income .
the state regulates construction , both in private and public hospitals , on the ground that public funds , in the form of federal , state and private health insurance programs , pay for virtually all capital improvements .
some of the big , teaching hospitals , such as presbyterian hospital , report a 1 to 2 percent drop in overall occupancy rates over the winter months .
some other hospitals , however , tend to confirm the state ' s projections . for example , the lutheran medical center in brooklyn reported a 17 percent drop in surgical - bed occupancy rates .
the beth israel medical center , a large teaching hospital at first avenue and 16th street that provides a wide range of sophisticated services , reported an overall 10 percent drop .
dr . robert newman , beth israel ' s director , said , ' ' there ' s no question that there has been a decrease in occupancy rates , particularly in surgery . ' '
dr . newman said beth israel ' s occupancy rate of 95 percent in 1983 had declined to 85 percent so far this year .
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“quite a few of our clients will lose their jobs , lose their housing or lose custody of their children” because they are held without bail while awaiting trial , despite a rule change intended to encourage pretrial release .
afety / reforms - intended - to - end - excessive - cash - bail - in - md - are - keeping - more - in - jail - longer - report - says / 2018 / 07 / 02 / bb97b306 - 731d - 11e8 - b4b7 - 308400242c2e _ story . html
crime / bs - md - ci - jerome - johnson - exonerated - 20180702 - story . html
in 2015 - 2016 , baltimore ' s schools had more police officers than counselors .
ue / baltimore _ girls _ report _ final _ 6 _ 26 _ 18 . pdf
“ [ w ] hile black girls make up about 80 percent of the female student body in bcps , they account for 95 percent of suspensions . ”
education / k - 12 / bs - md - ci - black - girls - school - 20180626 - story . html
great report . it shows that maryland could do more to expand compassionate release .
state compassionate release programs make sense for many reasons . yet how this area of our justice system works—or doesn’t—is unclear . “everywhere and nowhere : compassionate release in the states” aims to finally make sense of it all . read our report :
here is the flier for our latino residents . please share with all ! urltoken
instead of trying to get police to look more like social workers and health care providers , we should just hire social workers and health care providers .
dpscs has rescinded its book - limiting policy . inmates will now be allowed to receive books from family and third parties in the mail . additionally , there will not be a cap on the frequency by which inmates may order books from approved vendors . urltoken
policies need to reimagine how school police interact with youth to help end the school to prison pipeline .
education / k - 12 / bs - md - ci - school - police - policies - 20180607 - story , amp . html
help us get the word out : expungement clinic with the  @ naacpmd  montgomery county on june 21st ( juneteenth ) . getting a job , contributing to society & starting a life should be easier during reentry . urltoken
opd is hiring ! looking for a dedicated juvenile defender for our baltimore county team as well as an appellate litigator to join our appellate division .
opd training director patrice fulcher helping to close out # nlada # cod2018 moderating a discussion on implicit bias . urltoken
“your equity is in your staff . ” shannice anderson sharing how intake specialists and other core staff can initiate and lead public defender community activities . # cod2018 # nlada urltoken
sakinda skinner discusses opd prince george’s county’s care program . # cod2018 # nlada urltoken
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we are living in boom times for the private prison industry . the corrections corporation of america ( cca ) , the nation’s largest owner of private prisons , has seen its revenue climb by more than 500 percent in the last two decades . and cca wants to get much , much bigger : last year , the company made an offer to 48 governors to buy and operate their state - funded prisons . but what made cca’s pitch to those governors so audacious and shocking was that it included a so - called occupancy requirement , a clause demanding the state keep those newly privatized prisons at least 90 percent full at all times , regardless of whether crime was rising or falling .
all the big private prison companies—cca , geo group , and the management and training corporation—try to include occupancy requirements in their contracts , according to the report . states with the highest occupancy requirements include arizona ( three prison contracts with 100 percent occupancy guarantees ) , oklahoma ( three contracts with 98 percent occupancy guarantees ) , and virginia ( one contract with a 95 percent occupancy guarantee ) . at the same time , private prison companies have supported and helped write “three - strike” and “truth - in - sentencing” laws that drive up prison populations . their livelihoods depend on towns , cities , and states sending more people to prison and keeping them there .
mother jones was founded as a nonprofit in 1976 because we knew corporations and the wealthy wouldn’t fund the type of hard - hitting journalism we set out to do .
today , reader support makes up about two - thirds of our budget , allows us to dig deep on stories that matter , and lets us keep our reporting free for everyone . if you value what you get from mother jones , please join us with a tax - deductible donation so we can keep on doing the type of journalism that 2018 demands .
andy kroll is an investigative reporter at mother jones . for more of his stories , click here . follow him on twitter here . send tips , scoops , and documents to akroll ( at ) motherjones ( dot ) com .
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the youth first initiative has released a new report breaking down the walls highlighting the achievements of youth , families , and advocates in six states to help advance a new vision of youth justice . the report serves as a playbook for activists working to end the juvenile justice systems’ reliance on incarceration throughout the nation .
to accelerate the efforts to end harmful and inequitable youth incarceration , and to build on the work of the youth , families , and advocates who have fought successfully to close youth prisons , the youth first initiative looked at successful campaigns in six states , gathering lessons learned and strategies for success . “breaking down the walls” features these multi - year strategies and campaigns :
the strategies shared throughout this report are based on public documents as well as hours of conversations with youth , family members , and other advocates who generously gave their time to explain what they thought made their campaigns successful , as well as what they would do differently knowing what they do now .
the youth first initiative would like to acknowledge all the people who contributed to this effort . sheila bedi is the primary researcher and writer of this report with support from sue burrell , carmen daugherty , mishi faruqee , will harrell , grace bauer - lubow , lisa pilnik , liz ryan , marc schindler , david utter , and jill ward . the youth first initiative thanks : lisa pilnik , editor ; sarah baker , copy editor ; andy stepanian , designer ; and gladys carrion , tommy croft , tawanda davis , laura talkington - denies , chino hardin , andre holder , derrick johnson , michael mcintosh , lanita mitchell , amoretta morris , arja nelson , jonathan stith , jason wang , and ana yanez - correa .
you can make your voice heard by getting involved in a campaign to end youth incarceration in your state .


the " feedstock " ( coating precursor ) is heated by electrical ( plasma or arc ) or chemical means ( combustion flame ) .

thermal spraying can provide thick coatings ( approx . thickness range is 20 micrometers to several mm , depending on the process and feedstock ) , over a large area at high deposition rate as compared to other coating processes such as electroplating , physical and chemical vapor deposition .

they are fed in powder or wire form , heated to a molten or semimolten state and accelerated towards substrates in the form of micrometer-size particles .

resulting coatings are made by the accumulation of numerous sprayed particles .

the surface may not heat up significantly , allowing the coating of flammable substances .

coating quality is usually assessed by measuring its porosity , oxide content , macro and micro-hardness , bond strength and surface roughness .

generally , the coating quality increases with increasing particle velocities .

several variations of thermal spraying are distinguished : plasma spraying detonation spraying wire arc spraying flame spraying high velocity oxy-fuel coating spraying ( hvof ) high velocity air fuel ( hvaf ) warm spraying cold spraying in classical ( developed between 1910 and 1920 ) but still widely used processes such as flame spraying and wire arc spraying , the particle velocities are generally low ( < 150 m/s ) , and raw materials must be molten to be deposited .

plasma spraying , developed in the 1970s , uses a high-temperature plasma jet generated by arc discharge with typical temperatures > 15000 k , which makes it possible to spray refractory materials such as oxides , molybdenum , etc .

thermal spraying

suspension thermal spraying - an industrial breakthrough for thermal spraying [ pdf 0 . 27 mb ]
personnel and recources testing for the following processes : flame spraying with powder , flame spraying with wire , high speed flame spraying , arc spraying , plasma spraying , vacuum - plasma spraying , cold gas spraying .
high velocity oxygen fuel spraying ( hvof ) is a further development of flame spraying and detonation spraying .
an investigation of occupational metal exposure in thermal spraying processes . - pubmed - ncbi
thermal spraying with suspensions - hardware components for industrial use [ pdf 0 . 39 mb ]
p . fauchais and g . montavon , latest developments in suspension and liquid precursor thermal spraying ,
. while there may be variations in the applications of thermal spraying they all have similar risks .
thermal spraying has the capacity to form barrier and functional coatings on a wide range of substrates .
thermal spray coating techniques such as flame spraying , wire arc spraying and plasma spraying , allow many problems of wear , corrosion and thermal degradation to be resolved by engineering the surface with tailor - made coatings . for example , turbines can be coated by thermally spraying , allowing their use at higher temperatures .
many of the airborne dusts created by thermal spraying processes can be very hazardous to health if inhaled . it is therefore extremely important when installing thermal spraying systems that adequate dust control measures are incorporated .
coatings by thermal spraying of an amorphous precursor . j therm spray technol 20 ( 6 ) : 1201–1208
thermal spraying , which involves the unique process of melting and projecting a solid feedstock , has characteristics that are unlike other surface modification technologies . this section provides descriptions of various surface modification technologies including thermal spraying .
barbezat g ( 2006 ) application of thermal spraying in the automobile industry . surf coat technol 201 : 2028–2031
there are a number of hazards which must be considered when carrying out thermal spraying operations . these include :
thermal spraying is the general term used to describe a variety of coating processes . common processes described simply as
thermal spraying
include plasma spraying , hvof spraying , arc spraying and flame / combustion spraying . these processes have also been generally called
metallising
or
metal spraying .
while differing in method , all the listed processes are employed to add a coating to a substrate that , when combined , results in a
system
that is better suited to the engineering application than just the substrate alone .
the asm thermal spray society ( tss ) developed a new , free safety document , “guidelines for the use of personal protective equipment in thermal spraying , ” to help protect workers in thermal spray operations .
fukumoto m ( 2008 ) the current status of thermal spraying in asia ; hwang sy status of thermal spraying in korea ; li c - j the current state of thermal spray activities in china ; tani k , nakahira a the current status of thermal spray in japan ; khor mka thermal spray activities in singapore . j therm spray technol 17 ( 1 ) : 5–13
gorlach ia ( 2009 ) a new method for thermal spraying of zn–al coatings . thin solid films 517 : 5270–5273
starcoat® metal and carbide coating systems are applied with high - speed thermal spraying techniques to achieve exceptional wear resistance .
) . therefore , the larger spraying distances at hvsfs cause less heat flux compared to the very short spraying distances at sps processes .
cr2o3 high performance coatings by thermal spraying with suspensions ( annual report article 2016 ) [ pdf 0 . 17 mb ]
american welding society ( 1985 ) thermal spraying , practice , theory and application . american welding society , miami , fl
ducos m ( 2006 ) evaluating the costs of thermal spraying , aliderte course . aliderte , limoges ( in french )
petrovicova e , schadler ls ( 2002 ) thermal spraying of polymers . int mater rev 47 ( 4 ) : 169–190
atmospheric plasma spraying ( aps ) is especially suitable for depositing ceramics , in particular oxide ceramics for thermal barrier coatings .
low heat input . with few exceptions , the thermal spray process leaves the component’s thermal history alone .
) . moreover , spraying at such short distances makes the spray pattern rather complex and hinders spraying on small turbine blades , for example .
li y , li c - j , yang g - j , xing l - k ( 2010 ) thermal fatigue behavior of thermal barrier coatings with the mcraly bond coats by cold spraying and low - pressure plasma spraying . surf coat technol 205 : 2225–2233
a . potthoff , f . - l . toma , suspensions—ready for thermal spraying ? , e . meillot , ed . ,
hard chrome plating utilises more than double the number of process steps compared to thermal spraying . this translates into processing time , giving significantly longer turnaround times for chrome plating than thermal spray .
coating by spraying the coating material in the molten state , e . g . by flame , plasma or electric discharge characterised by the method of spraying
p . müller , a . killinger , and r . gadow , comparison between high - velocity suspension flame spraying and suspension plasma spraying of alumina ,
thermal spraying as a process group offers universal opportunities in the application of various functional layers , for repair or the production of components .
application time is much slower than thermal spraying . even for 0 . 001 inches , the plating process can take at least one hour
capital cost - the relative capital expenditure for establishing facilities with the same production capability is much greater for chrome plating than thermal spraying .
e . bakan , d . e . mack , g . mauer , and r . vaßen , gadolinium zirconate / ysz thermal barrier coatings : plasma spraying , microstructure and thermal cycling behavior ,
thermal spraying is a coating process that generally applies a powdery or a wire - shaped coating material by spinning it with high thermal energy onto a component surface , where it creates a coating .
thermal spraying with suspensions uses a liquid feedstock instead of a spray powder and has evolved into a well - established technology at least in the academic field . both important powder spray technologies , namely plasma spraying and high velocity oxy - fuel spraying , are capable of processing a liquid feedstock .
there are many variations of thermal spraying technology . in flame spraying the combustion of a fuel gas is used to heat the material . in atmospheric plasma spraying ( aps ) the material is melted and accelerated in a plasma jet . to avoid oxidation of the feed material , spraying can be carried out in an inert gas atmosphere , at a reduced pressure ( known as vacuum plasma spraying vps or low pressure plasma spraying lpps ) . in high velocity oxy - fuel spraying ( hvof ) , material is injected into a high velocity jet generated by burning a fuel mixed with oxygen at high pressure .
m . vardelle and j . l . besson : “γ - alumina obtained by arc plasma spraying : a study of the optimization of spraying conditions , ”
kokini k , dejonge j , rangaraj s , beardsley b ( 2002 ) thermal shock of functionally graded thermal barrier coatings with similar thermal resistance . surf coat technol 154 : 223–231
gilbert a , kokini k , sankarasubramanian s ( 2008 ) thermal fracture of zirconia–mullite composite thermal barrier coatings under thermal shock : a numerical study . surf coat technol 203 : 91–98
the asm thermal spray society operates according to our vision statement :
to be the leading global source for thermal spray information – tss , your thermal spray information partner .
e . bakan , d . e . mack , g . mauer , and r . vaßen , gadolinium zirconate / ysz thermal barrier coatings : plasma spraying , microstructure , and thermal cycling behavior ,
thermal spraying is a coating process whereby , in most cases , a powdery or a wire - shaped coating material with high thermal energy is spun onto a component surface where it creates a layer .
gfe has more than 20 years of experience in the field of thermal spraying and carries out coating services for almost all segments of industry .
share your stories and questions in the comments section below to join the conversation on making thermal spraying processes as safe and efficient as possible .
gérard b ( 2006 ) application of thermal spraying in the automobile industry . surf coatings technol 201 ( 5 ) : 2028–2031 . doi :
flame spraying requires line of sight to the surface being coated , similar to all other thermal spraying processes . it is difficult , or impossible , to coat inner surfaces of small diameter bores and other restricted access surfaces .
karger m , vaßen r , stöver d ( 2011 ) atmospheric plasma sprayed thermal barrier coatings with high segmentation crack densities : spraying process , microstructure and thermal cycling behaviour . surf coat technol 206 : 16–23
competitive application costs - when parts are large enough and the coating thickness requirement is high , thermal spraying becomes very cost competitive with chrome plating .
thermal sprayed coatings are typically applied to metal substrates , but can also be applied to some plastic substrates . thermal sprayed coatings uniquely
d . zhu and r . miller , thermal conductivity and elastic modulus evolution of thermal barrier coatings under high heat flux conditions ,
thermal barrier coatings ( tbcs ) depend on low thermal conductivity and thermal diffusivity . the state - of - the - art tbc system at the moment is an air plasma sprayed zr0 2 / 6 - 8wt % y 2 0 3 ceramic layer over a nicraly bond coat layer , deposited by plasma spraying at low pressure . partially stabilised zirconia has been chosen as the top coat because of its excellent thermal shock resistance , low thermal conductivity and relatively high coefficient of thermal expansion . the thermal conductivity and strain tolerance is further enhanced by the microcrack network , figure 1 , produced in the individual splats due to spraying .
fauchais p . l . , heberlein j . v . r . , boulos m . i . ( 2014 ) industrial applications of thermal spraying technology . in : thermal spray fundamentals . springer , boston , ma
uniform coating thickness - the coating build - up with thermal spraying is much more uniform over the entire part , depending on automation and part geometry .
low - pressure plasma spraying ( lpps ) and vacuum plasma spraying ( vps ) permit ceramic and especially also metallic layers to be produced , while oxygen uptake is avoided .
the demands for engineering coatings are becoming more and more stringent . environmental concerns are also being considered as an integral part of the design process . for future economic competitiveness and a lower environmental impact we must therefore turn our attention to processes that use the minimum of resources . thermal spraying is an attractive coating technique as it offers a wide choice of materials and processes that have a reduced impact on the environment when compared to conventional plating processes . thermal spray coating techniques such as hvof , flame wire spraying , flame powder spraying , arc wire spraying , plasma spraying and cold gas spraying , allow many problems of wear , corrosion and thermal degradation to be resolved by engineering the surface with tailor - made coatings .
a . killinger , m . kuhn , and r . gadow , high - velocity suspension flame spraying ( hvsfs ) , a new approach for spraying nanoparticles with hypersonic speed ,
> > leistner hans gmbh > > . : : . plastic coating . : : . thermal spraying . : : . whirl sinter . : : .
liang b , ding c ( 2005 ) thermal shock resistances of nanostructured and conventional zirconia coatings deposited by atmospheric plasma spraying . surf coat technol 197 : 185–192
all in all , it is easy to see why thermal spraying has become the preferred surface engineering technology in the market due to the amount of advantages it has over hard chrome plating . when it comes to disadvantages , we can also see that hard chrome plating has more issues to overcome than thermal spraying .
j . francel and w . d . kingrey : “thermal conductivity : iv , apparatus for determining thermal conductivity by a comparative method ,
this invention relates generally to a plasma transfer wire arc thermal spray system and a method of thermally spraying materials and , in particular , to a thermal spray apparatus with a spray gun having a simplified and faster starting procedure .
nanostructured powders by atmospheric plasma spraying . j therm spray technol 17 ( 3 ) : 329–337
abb has invested in a development center for new products , and one new technology being employed is hvaf thermal spraying . they primarily use this new thermal spray process to improve the quality and lifetime of the new products they manufacture .
j . francl and w . d . kingery : “thermal conductivity : ix , experimental investigation of effect of porosity on thermal conductivity , ”
thermal spray wires are used in thermal spraying applications by feeding two wires into a spray gun , then generating an arc between the two wires to create molten feedstock that is transferred onto a surface to deliver a heavy coating . thermal spray wires prove to be corrosion resistant in a number of demanding environments .
thermal spraying offers a number of benefits , including improved resistance to wear , corrosion and heat in the final product . there are a number of thermal spraying processes , which basically entail heating the powder to above its melting temperature . cold spraying , in contrast , requires a powder temperature of just a few hundred degrees celsius . proper adhesion of the coating is achieved by increasing the particle velocity and thus the kinetic energy .
moskowitz ln ( 1993 ) application of hvof thermal spraying to solve corrosion problems in the petroleum industry—an industrial note . j therm spray technol 2 ( 1 ) : 21–29
r . tiwari , h . herman , and s . sampath , vacuum plasma spraying of mosi
a number of materials have already been proven to be suitable for cold spraying . these include :
zhou d , guillon o , vaßen r . development of ysz thermal barrier coatings using axial suspension plasma spraying . coatings . 2017 ; 7 ( 8 ) : 120 .
the success of the process in the automotive industry is due to the wide range of materials available for thermal spraying , the properties of these materials and the ease in providing high - rate / low - cost deposition for the high volume of parts involved . thermal spraying is a versatile process that can easily be integrated into a production line .
a . guignard , g . mauer , r . vassen , and d . stöver , deposition and characteristics of submicrometer - structured thermal barrier coatings by suspension plasma spraying ,
waste disposal - wastes from thermal spraying are not toxic , but do contain elements requiring special disposal . typically they are dry powders , some of which can be reactive .
the main frame of work of the thermal spraying group consists of the development of new spraying technologies ( such as suspension spraying ) , new coating solutions ( such as coatings for heating elements , thermoelectric modules or hard metal coatings for components subjected to high stress ) , as well as the characterization of coatings ( for example , laser acoustic surface waves – lawave® ) .
plasma spraying produces a high quality coating by a combination of a high temperature , high energy heat source , a relatively inert spraying medium and quite high particle velocities , typically 200–300 m / s .
thermal spraying can provide coatings with an approximate thickness range of 20 micrometers to several millimeters depending on the process and feedstock . coating materials available for thermal spraying include metals , alloys , ceramics , plastics and composites . coating quality is usually assessed by measuring its porosity , oxide content , macro and micro - hardness , bond strength and surface roughness .
zhu d , choi sr , miller ra ( 2004 ) development and thermal fatigue testing of ceramic thermal barrier coatings . surf coat technol 188–189 : 146–152
plasma spraying makes use of the plasma torch as the main tool for heating and spraying the coating . after the powder material has been melted down , it is then placed on the product in a manner which is similar to combustion flame spraying . the coatings which result from plasma spraying may be a few micrometers thick to a few millimeters think . while powder is the most widely used material , metals and ceramics are also used . the plasma spraying process is highly popular due to its adaptability .
there are a number of different process variations , for example plasma spraying , high - speed flame spraying or arc spraying , which are used for processing a broad range of materials such as metals , ceramics and polymers into functional coatings . layer thicknesses range from approx . 30 µm to several millimetres .
: flsp was the first thermal spraying process . it use 2760 ºc ( 5000 ºf ) oxyacetylene flame to melt the targets which may be powders , rods , or wires .
zhou , d . ; guillon , o . ; vaßen , r . development of ysz thermal barrier coatings using axial suspension plasma spraying . coatings 2017 , 7 , 120 .
wang y , khor ka , cheang p ( 1998 ) thermal spraying of functionally graded calcium phosphate coatings for biomedical implants . j therm spray technol 7 ( 1 ) : 50–57
the lead taken in evaluating and utilising thermal spraying on previously plated components by the major airlines in the us and europe , and other high volume , high profile users of chrome plating , should reinforce the confidence level of other industries enough to evaluate what thermal spraying can provide . the advances in thermal spraying over the past 10 years , both in terms of product and process , and also in the level of understanding , now positions this technology to move forward on a broader front as an established , and thoroughly proven industrial tool .
layers in power electronics using cold gas spraying . j therm spray technol 20 ( 1–2 ) : 299–306
deposits fabricated by radio frequency induction plasma spraying . j therm spray technol 10 ( 4 ) : 611–617
low - pressure thin - film plasma spraying ( lpps - tf ) represents a further development of vacuum plasma spraying conducted at low pressure . it enables thin , gas - tight layers to be deposited .
g . mauer , a . guignard , and r . vaßen , plasma spraying of efficient photoactive tio
like overlay welding or chromium plating , thermal spraying is a coating process . the feedstock material , in the form of a wire or powder , is melted or softened by flame or electricity and propelled onto the workpiece . during coating application , the spray torch traverses the workpiece to produce a coating . as with all industrial processes , thermal spraying has its advantages and limitations . understanding these characteristics is the key to taking advantage of thermal sprayed coatings . some of the benefits of thermal spray coatings include the following .
curry n , donoghue j ( 2012 ) evolution of thermal conductivity of dysprosia stabilised thermal barrier coating systems during heat treatment . surf coat technol 209 : 38–43
the other function of the thermal spraying enclosure is to reduce the noise to acceptable levels . typically , noise levels between 120 and 130 dba can be generated whilst spraying and , in order to comply with coshhh regulations , this needs to be reduced below 80 dba at 1 metre .
there are a number of different process variations , for example plasma spraying , high - speed flame spraying or arc spraying , which are used for processing a broad range of materials , such as metals , ceramics and polymers , into functional coatings . layer thicknesses range from approx . 30 µm to several millimeters .
helali m , hashmi msj ( 1996 ) production of free - standing objects by high velocity oxy - fuel ( hvof ) thermal spraying process . j mater process technol 56 : 431–438
thermal spraying is used in particular for wear - resistant combination layers , where an extreme surface hardness is to be combined with non - stick and sliding properties or enhanced traction properties .
at a & a coatings , we recognize the various associated with thermal spray processes . that’s why we adhere to the regulations set by the occupational safety & health administration to keep our workplaces safe . our team of highly trained thermal spraying specialists and operators understand the risks and know the importance of following safety procedures so that we can mitigate the risks . below is a quick look at how we ensure workplace safety while using thermal spraying equipment :
a & a coatings has been around for more than seven decades . we are the go - to shop for stellar thermal spraying solutions as we can tailor high performance thermal spray coatings according to your specific requirements . our success is not only built upon our diverse capabilities , which include plasma spraying , spray and fuse hardfacing , metalizing and hvof , but our ability to maintain absolute thermal spray safety in our workplace . find out the common risks that are associated with operating a thermal spray workplace and how we mitigate those risks .
effect of thermal barrier coating for the improvement of si engine performanc . . .
the microstructural features in a tbc also influence its thermal properties . in fig .
s . mahade , n . curry , s . björklund , n . markocsan , and p . nylén , thermal conductivity and thermal cyclic fatigue of multilayered gd
find out how metalworkers like you can address the issue of thermal spray fumes .
figure 1 this thermal spray application uses a combustion source as the delivery mechanism .
döring j - e , hoebener f , langer g ( 2008 ) review of applications of thermal spraying in the printing industry in respect to oems . in : lugscheider e ( ed ) thermal spray conference : crossing the border . dvs , düsseldorf , e - proc
y . zhao , d . li , x . zhong , h . zhao , l . wang , f . shao , c . liu , and s . tao , thermal shock behaviors of ysz thick thermal barrier coatings fabricated by suspension and atmospheric plasma spraying ,
luo l , liu s , li j , wu y ( 2011 ) thermal shock resistance of femncral / cr3c2–ni9al coatings deposited by high velocity arc spraying . surf coat technol 205 : 3467–3471
from a historical view - point the thermal spraying or metal spraying has got its beginnings in the production of metal powders and was patented for the first time in 1882 . thereby , high - tension gases or vapours were made to escape and liquid metal was poured into the stream of gas (
vacuum plasma spraying ( vps ) / technologies | tocalo co . , ltd . comprehensive manufacturer of advanced coating
workers involved in thermal spray processes face serious risks . this process—also known as metalizing , flame spraying , metal spraying and hardfacing—involves melting metal and spraying it onto a surface to form a coating . this is useful for adding corrosion - resistance to surfaces , building up worn parts and other applications . any situation that includes extreme heat and melted metal requires precautions , but workers performing thermal spray are often not protected to the degree that workers in other dangerous fields are , such as welders .
do you know why thermal spray coating has replaced hard chrome plating as the preferred surface treatment for many applications across a wide array of industries ? in this post , you will learn the answer as we put thermal spraying and hard chrome plating side by side for comparison .
as with all thermal spraying processes there are particular health and safety issues that need to be addressed . for flame spraying these relate to protecting the operator from powder , dust and fume . also the use of flammable gases , including acetylene , requires that safe use and storage of gases be considered .
thermal metal spraying , also referred to as thermal spray or metalizing , is a process where molten or semi - molten materials are propelled towards a substrate and deposited on the surface to create a coating that enhances the substrate’s properties or characteristics . spraying materials may include pure metals , alloys , ceramics , cermets or plastics and can be delivered in a powder , wire or rod forms . some common thermal spraying processes include plasma arc spray , combustion spray , electric arc spray , wire flame spray , high velocity oxy - fuel ( hvof ) spray , cold spray and powder flame spray . thermal metal spraying is used across a wide range of industries and applications where metalworking is common including automotive , agriculture , aerospace , gas turbines , gas or petro - chemical .
a typical example of such an application of thermal spraying—although not constricted to such use—is the coating of light metal engine cylinder blocks with low friction and thermally conductive coatings on the cylinder bore walls .
thermal spraying can provide thick coatings ( approx . thickness range is 20 micrometers to several mm , depending on the process and feedstock ) , over a large area at high deposition rate . coating materials available for thermal spraying include metals , alloys , ceramics , plastics and composites . they are fed in powder or wire form , heated to a molten or semimolten state and accelerated towards substrates in the form of micrometer - size particles . combustion or electrical arc discharge is usually used as the source of energy for thermal spraying . resulting coatings are made by the accumulation of numerous sprayed particles
ivosevic m , coguill sl , galbraith sl ( 2009 ) polymer thermal spraying : a novel coating process . in : marple br , hyland mm , lau y - c , li c - j , lima rs , montavon g ( eds ) thermal spray 2009 : proceedings of the international thermal spray conference . asm international , materials park , oh , pp 1078–1083
sundararajan g , mahajan yr , joshi sv ( 2009 ) thermal spraying in india : status and prospects . in : marple br , hyland mm , lau y - c , li c - j , lima rs , montavon g ( eds ) thermal spray 2009 : proceedings of the international thermal spray conference . asm international , materials park , oh , pp 511–516
during powder flame spraying the continuously added powder - like spraying additive is pre - melted and melted in an acetylene - oxygen flame . it is sprayed onto the prepared work piece surface , accelerated by the expanded fuel gases .
however , suspension plasma spraying ( sps ) processes were rapidly developing in parallel . gitzhofer et al . ( ref
p . müller , a . killinger , and r . gadow , suspension spraying of alumina and zirconia ceramics ,
finally , this article will conclude with the required improvements to meet the coating industry standards with suspension plasma spraying .
p . blazdell and s . kuroda , plasma spraying of submicron ceramic suspensions using a continuous ink jet printer ,
m . yamada , h . isago , h . nakano , and m . fukumoto , cold spraying of tio
zhou , dapeng ; guillon , olivier ; vaßen , robert . 2017 .
development of ysz thermal barrier coatings using axial suspension plasma spraying .
coatings 7 , no . 8 : 120 .
surface coverage might not be as easy to achieve in the case of plating . this is because thermal spraying is after all a line of sight process and it is harder to coat interior diameters .
when comparing the two processes , a consideration of the economics involved in establishing and maintaining both types of facilities can be made . the following factors make thermal spraying commercially competitive with hard chrome plating .
d . cheng , g . trapaga , j . w . mckelliget , and e . j . lavernia , mathematical modelling of high velocity oxygen fuel thermal spraying of nanocrystalline materials : an overview ,
thermal spraying is a cost - effective method for enhancing surface properties . we support all common thermal spray methods , with options to suit your surfacing and all other applications requirements – such as the size of your run , scale of your part , environmental concerns , and portability needs .
interested to add thermal spray , laser cladding and cold spray solutions to your portfolio .
n . curry , k . vanevery , t . snyder , and n . markocsan , thermal conductivity analysis and lifetime testing of suspension plasma - sprayed thermal barrier coatings ,
a . r . nicoll and h . eschnauer , retesting thermal - spray powders ,
/ ysz thermal barrier coatings . j therm spray technol 19 ( 6 ) : 1179–1185
thermal spray operator arc sprays copper onto a used ink drum for reclamation purposes . .
high velocity oxygen fuel ( hvof ) spraying refers to a group of thermal spraying processes where spraying is done at supersonic speeds . hvof is considered to be a smart technique due to its wide range of choices in terms of materials and processes . it has less of an impact on the environment in comparison to other conventional plating processes . the materials available for hvof spray coating include metals and alloys , ceramics , plastics and composites .
starcoat® metal and carbide coating systems are applied with high - speed thermal spraying techniques to achieve exceptional wear resistance . the low proportion of pores creates an extremely high surface hardness of up to 70 hrc .
e . dongmo , r . gadow , a . killinger , and m . wenzelburger , modeling of combustion as well as heat , mass , and momentum transfer during thermal spraying by hvof and hvsfs ,
e . meillot , s . vincent , c . caruyer , j . p . caltagirone , and d . damiani , from dc time - dependent thermal plasma generation to suspension plasma - spraying interactions ,
davis jr ( ed ) ( 2004 ) handbook of thermal spray technology . sections introduction to applications for thermal spray processing and selected applications . asm international , materials park , oh
notomi a , sakakibara n ( 2009 ) recent application of thermal spray to thermal power plants . in : marple br , hyland mm , lau y - c , li c - j , lima rs , montavon g ( eds ) thermal spray 2009 : proceedings of the international thermal spray conference . asm international , materials park , oh , pp 1106–1111
n . curry , k . van every , t . snyder , and n . markocsan , thermal conductivity analysis and lifetime testing of suspension plasma - sprayed thermal barrier coatings ,
thermal spray coatings are widely used in a variety of industrial applications . molten powder or wire is heated either through oxy - fuel combustion or plasma—the flame of the spray device powers the heated mixture , and after even spray distribution onto a metal product , the mixture assumes its solid coating form . thermal spray coatings can serve an array of functions ; commonly used to treat planes , they can also protect products from wear , temperature extremes , chemicals , and even protect buildings from external environmental conditions like rain and humidity . although there are multiple methods and materials involved in thermal coating , they are distinguished by both heat source and the base material used for deposition . combustion flame spraying , high velocity oxy - fuel spraying ( hvof ) , two - wire electric arc spraying , plasma spraying , and vacuum plasma spraying are several common coating application processes .
ph . roumilhac , j . f . coudert , and p . fauchais , designing parameters of spraying plasma torches ,
smyth rt , anderson jc ( 1975 ) production of resistors by arc plasma spraying . electrocompon sci technol 2 : 135–145
in contrast to plasma spraying , high - velocity flame spraying permits significantly higher particle velocities at comparatively moderate temperatures of the hot gas torch . this means that the process is particularly suitable for wear - resistant alloys and mcraly bond coats .
coating by spraying the coating material in the molten state , e . g . by flame , plasma or electric discharge
high velocity oxygen fuel ( hvof ) spraying is a thermal spraying coating technique used to enhance surface properties or dimensions of components . this coating provides longer life of equipment through significantly increasing the protection against erosion , wear resistance and corrosion . the first hvof process is used in the detonation gun ( d - gun ) process .
a few months ago we looked at the thermal spraying of cylinder liners but here i would like to examine one of the processes mentioned in more detail , the plasma transferred wire arc ( ptwa ) method .
we conduct regular air sampling to determine our workers’ potential exposure to airborne contaminants . we will make sure that the gases that are created from our thermal metal spraying and practices to exceed the permissible exposure limits .
d . r . clarke and s . r . phillpot , thermal barrier coating materials ,
–nicr vps thermal spray coatings as candidate for chromium replacement . surf coat technol 220 : 225–231
r . j . bratton and s . k . lau , zirconia thermal barrier coatings ,
e . ingier - stocka and m . maciejewski , thermal decomposition of [ co ( nh
space - a thermal spray facility requires significantly less floor space than an equivalent plating facility .
on - site capability - thermal spray equipment is portable and has on - site capability .
fewer process steps - thermal spray coatings require fewer process steps to apply than chrome plating .
please contact astro alloys for custom design specs and recommendations for your specific thermal spray operations .
at the surface engineering institute , numerical investigations of all relevant thermal spraying processes are executed . due to the different scales and physical phenomena that occur through thermal spraying processes , the processes can not be analyzed by deployment of a single numerical model . the entire process beginning from the heat generation up to the coating formation must be divided into sub - processes , which have to be modeled separately ( see figure left ) .
all methods of thermal spraying involve the projection of small softened particles onto a cleaned and prepared surface where they adhere to form a continuous coating . combined thermal and kinetic energy causes the particles to flatten or ’splat’ onto the surface , and onto each other , to produce a cohesive coating of successive layers .
the document provides guidelines for establishing ppe programs for thermal spraying , assessing hazards associated with thermal spray operations and training workers about ppe , as well as guidelines for selecting , using and maintaining ppe . the information is consistent with osha’s personal protective equipment standard ( 29 cfr 1910 . 132 - 138 ) .
a . ganvir , n . curry , s . björklund , n . markocsan , and p . nylén , characterization of microstructure and thermal properties of ysz coatings obtained by axial suspension plasma spraying ( asps ) ,
p . fauchais and a . vardelle , innovative and emerging processes in plasma spraying : from micro - to nanostructured coatings ,
j . oberste berghaus , b . marple , and c . moreau , suspension plasma spraying nanostructured wc - 12co coatings ,
f . wu et al . method for preparing porous hydroxyapatite coatings by suspension plasma spraying , patent wo 2010130109 a1 , 2010
thermal spraying is a technology which improves or restores the surface of a solid material . the process can be used to apply coatings to a wide range of materials and components , to provide resistance to : wear , erosion , cavitation , corrosion , abrasion or heat . thermal spraying is also used to provide electrical conductivity or insulation , lubricity , high or low friction , sacrificial wear , chemical resistance and many other desirable surface properties .
during thermal spraying , the heat applied to the base material can be extremely high . when coating thin - walled substrates or substrates with very low thermal conductivity , or when using temperature - sensitive coating materials , overheating problems can arise . differences in heat expansion rates can even cause the coating to flake off .
hvof coatings are used in applications requiring the highest density and strength not found in most other thermal spray processes . new applications , previously not suitable for thermal spray coatings are becoming viable .
thermal sprayed coatings can also be used to manufacture hybrid microelectronic components , by spraying ceramic materials onto a metal substrate to provide electrically insulating areas . such technology is becoming increasingly important in meeting the demands of modern computing .
chen x , gu l , zou b , wang y , cao x ( 2012 ) new functionally graded thermal barrier coating system based on lamgal11o19 / ysz prepared by air plasma spraying . surf coat technol 206 : 2265–2274
mihm s , duda t , gruner h , thomas g , dzur b ( 2012 ) method and process development of advanced atmospheric plasma spraying for thermal barrier coatings . j therm spray technol 21 ( 3–4 ) : 400–408
henne rh , schitter c ( 1995 ) plasma spraying of high performance thermoplastics . in : berndt cc , sampath s ( eds ) thermal spray science and technology . asm international , materials park , oh , pp 527–532
thermal spraying is a surface modification technology in which metals and ceramics are heated to a molten or semi - molten state and then made to collide with and accumulate on the surface of a substrate thereby forming a coating .
all five thermal spray processes can be used to apply ‘engineering coatings’ to modify the surface properties of an item . engineering coatings can provide such properties as enhanced wear resistance , thermal barriers , electrical / thermal conductivity , hard - chrome replacement and insulation across a wide range of applications .
schlegel n . , d . sebold , y . j . sohn , g . mauer , r . vaßen , thermal cycling performance of a columnar structured complex perovskite in a temperature gradient test , e . meillot ed . , workshop on suspension and solution thermal spraying , tours france oct 8 , 9 , 2014
since the first thermal spraying process for feeding tin and lead wires into a modified oxyacetylene welding torch patented by m . u . schoop ( zurich , switzerland ) between 1882 and 1889 , thermal spray technology has been continuously developed to meet market requirements . it has evolved into a large family of processes that now includes flame spray , electric arc spray , plasma arc spray , and more recently the high kinetic energy spraying known as cold spray .
- jim grundtner and precision coatings , inc . are among a prestigious few in thermal spray .
state - of - the - art thermal spray coating solutions [ pdf 0 . 34 mb ]
pawlowski l ( 1995 ) the science and engineering of thermal spray coatings . wiley , new york
iyengar rk ( 2009 ) thermal spray coating for steel processing . technovations international , littleton , ma
cpt , thermal spray center , center within the university of barcelona which carries out an extensive research on the thermal spray field ; it covers a wide range of materials suitable for many applications .
figure 3 . a gas turbine shaft previously chrome plated , now coated using thermal spray techniques .
in the future the manufacturing and engineering industries will continue to change dramatically , and for numerous engineering or consumer durable products appropriate surface engineering as applied by thermal spraying techniques is becoming a decisive factor in sustaining a competitive edge .
berthelsen r , wiederkehr t , denzer r , menzel a , müller h ( 2014 ) efficient simulation of nonlinear heat transfer during thermal spraying of complex workpieces . world j mech 04 ( 09 ) : 289–301 . doi :
since then , numerous activities have been undertaken to evaluate sps and solution plasma precursor spraying ( spps ) processes , mainly in the field of thermal barrier coating ( tbc ) and solid oxide fuel cell ( sofc ) research . soon it was recognized that sps coatings revealed a unique microstructure that could not be achieved by ordinary spray processes like plasma and combustion flame spraying . in parallel , spraying of liquid precursors for the fabrication of nano - scaled powders and deposits were investigated ( ref
gross ka , kovalevskis a ( 1996 ) mold manufacture with plasma spraying . j therm spray technol 5 ( 4 ) : 469–475
n . markocsan , a . ganvir , and p . newbatt , influence of coating morphology on thermal properties and lifetime of axial suspension plasma sprayed thermal barrier coatings , invited talk at the “thermal spray of suspensions & solutions symposium ( ts4 ) ” , montreal , 2 - 3 december , 2015
haynes ja , ferber mk , porter wd ( 2000 ) thermal cycling behavior of plasma - sprayed thermal barrier coatings with various mcraix bond coats . j therm spray technol 9 ( 1 ) : 38–48
s . gong , k . vanevery , h . wang , and r . w . trice , microstructure and thermal properties of inflight rare - earth doped thermal barriers prepared by suspension plasma spray ,
the substitution of the conventional spray powders by suspensions offers new possibilities , such as the direct use of finely dispersed powders , and thus saving in the production of specific thermal spraying feedstock powder , and the production of nanostructured coatings .
skandan g , yao r , sadangi r , kear bh , qiao y , liu l , fischer te ( 2000 ) multimodal coatings : a new concept in thermal spraying . j therm spray technol 9 ( 3 ) : 329–331
pan zy , wang y , wang ch , sun xg , wang l ( 2012 ) the effect of sic particles on thermal shock behavior of al2o3 / 8ysz coatings fabricated by atmospheric plasma spraying . surf coat technol 206 : 2484–2498
with ceracoat® , high - quality metal and ceramic coatings are created in a thermal spraying process . extreme surface hardness optimizes the wear resistance and traction properties and extends the service life of components subjected to high levels of mechanical strain .
thermal conductivity , thermal cyclic life and erosion resistance of the three different tbc designs were compared . the as - sprayed tbcs were subjected to thermal cyclic fatigue test at 1100 °c and 1200 °c . also , the thermal conductivity of as - sprayed tbcs was measured in the temperature range of 25 °c to 1000 °c . the results revealed that the gz - based multilayered tbcs had a higher thermal cyclic life and lower thermal conductivity compared to single - layer ysz tbc , with the life enhancement in the thermal cyclic tests carried out at 1300 °c being significant ( 43 cycles in case of ysz compared to 395 and 521 cycles for the double - and triple - layer tbcs discussed above ( ref
spraying humiseal® uv50lv can be applied via standard selective coating equipment or by conventional hand spray equipment . the source air used for spraying must be dry ( a dry inert gas ( air , nitrogen or argon ) is highly recommended ) to prevent premature curing of the secondary cure mechanism . the spraying should be done with adequate ventilation so that the vapour and mist are carried away from the operator .
thermal spraying means to cause a molten material to collide with and accumulate on the surface of a substrate . accordingly , in order to create a good thermal spray coating , a high - temperature state to create a sufficient molten state and a high - speed state to spray particles are required . in the film - creation process in thermal spraying , molten particles collide with the substrate and simultaneously become flattened . some particles become a spray and are scattered . particles of the raw material that have melted and become a liquid , build up rapidly to form a film .
several elements are contained within the spraying layer and can be combined ( e . g . cr , ni , carbides etc . )
) . however , the deposition efficiency is considerably reduced in this case due to only partial melting of the particles during spraying . figure
s . sampath , ph . d . thesis , “rapid solidification during plasma spraying , ” suny at stony brook , aug 1989 .
j . oberste - berghaus , b . marple , and c . moreau , suspension plasma spraying of nanostructured wc - 12co coatings ,
r . gadow , a . killinger , and j . rauch , new results in high velocity suspension flame spraying ( hvsfs ) ,
e . bouyer , f . gitzhofer , and m . i . boulos , the suspension plasma spraying of bioceramics by induction plasma ,
the at 400 wire arc spray system has the highest deposition rate of the thermal spraying processes . options are available for broad coverage or tight spray patterns , running gear , cable length , remote wire feed unit and id coating extension .
nagai m , shigemura s , yoshiya a ( 2009 ) thermal - sprayed cfrp roll with resistant to thermal shock and wear - for papermaking machine . in : marple br , hyland mm , lau y - c , li c - j , lima rs , montavon g ( eds ) thermal spray 2009 : proceedings of the international thermal spray conference . asm international , materials park , oh , pp 607–611
the atmospheric plasma spray process is used for wear and corrosion protection , thermal insulation , repair , and restoration . as it is the most flexible of all thermal spray processes coatings , can be applied …
high deposition rates - most of the thermal spray processes have a higher deposition rate than chromium plating .
thermal spraying is widely adopted across many industries as a preferred method . it has huge scope to extend the life of new components or through the use of tried and tested techniques , to repair and re - engineer worn or damaged components .
thermal spraying techniques are coating processes in which melted ( or heated ) materials are sprayed onto a surface . the
feedstock
( coating precursor ) is heated by electrical ( plasma or arc ) or chemical means ( combustion flame ) .
our wire feeding solutions for electric arc thermal spraying offer you consistent feed rates , speed adjustment , and the ability to interface with various spool types or even whole drums . wires are uncoiled and transported using push or push - pull mechanisms .
more recently , thermal spraying has been recognised as a key process for the synthesis of specialised coatings and materials . it offers the ability to create free standing structures for net - shaped manufacture of high performance ceramics , composites and functional graded materials . it is also used for the rapid - solidification synthesis of specialised materials . thermal spraying is now being considered for the synthesis of advanced functional surfaces such as catalytic coatings , dielectrics , ferrites , bioactive materials and solid oxide fuel cells .
the customer was investigating dust collection for a thermal spraying booth . they had been using scrubbers and bag filters , but with both of these the filters became clogged within about a week , and the customer had problems with reduced air volume .
especially in sps , the short spraying distances cause high heat flux to the substrate . spraying distances at sps processes is usually 50 mm or even lower . using hvsfs larger spraying distances are used , usually between 80 and 120 mm . besides the lower spraying distance compared to the use of powders also the solvents influences the heat flux . when water is used energy is needed for the vaporization of the water . using organic solvents additional energy can be generated by the combustion of this solvent . therefore , the used solvent also influences the heat flux .
lima rs , marple br ( 2007 ) thermal spray coatings engineered from nanostructured ceramic agglomerated powders for structural , thermal barrier and biomedical applications : a review . j therm spray technol 16 ( 1 ) : 40–63
koolloos mfj , houben jm ( 2000 ) behavior of plasma - sprayed thermal barrier coatings during thermal cycling and the effect of a preoxidized nicraiy bond coat . j therm spray technol 9 ( 1 ) : 49–58
thermal spraying is a widely applied coating technique . the optimisation of the thermal spraying process with respect to temperature or temperature induced residual stress states requires a numerical framework for the simulation of the coating itself as well as of the quenching procedure after the application of additional material . this work presents a finite element framework for the simulation of mass deposition due to coating by means of thermal spraying combined with the simulation of nonlinear heat transfer of a rigid heat conductor . the approach of handling the dynamic problem size is highlighted with focus on the thermodynamical consistency of the derived model . with the framework implemented , numerical examples are employed and material parameters are fitted to experimental data of steel as well as of tungsten - carbide–cobalt - coating .
chráska p , neufuss k , herman h ( 1997 ) plasma spraying of zircon . j therm spray technol 6 ( 4 ) : 445–448
chraska p , neufuss k , herman h ( 1997 ) plasma spraying of zircon . j therm spray technol 6 ( 4 ) : 445–448
* as the spraying speed of molten particles is faster than in the air , coatings with higher bonding strength and higher density are produced .
r . vaßen , h . kaßner , g . mauer , and d . stöver , suspension plasma spraying : process characteristics and applications ,
l . jia and f . gitzhofer , induction plasma synthesis of nanostructured sofcs electrolyte using solution and suspension plasma spraying : a comparative study ,
r . vassen , h . kassner , g . mauer , and d . stöver , suspension plasma spraying : process characteristics and applications ,
combustion flame spraying is an excellent option for surfaces which aren’t designed to handle extreme stress . the coating which results from this process is not strongly attached to the surface since the spraying mechanism is powered by a lower flame velocity . the flame will be generated via oxygen which has been combined with fuel , and this will melt the mixture . combustion flame spraying is popular for low intensity applications due to its low cost .