別紙4 (課程博士)
Date of submission

平成 28Department

年

07月15日S加dentΦNumber

機械工学専攻Pplica11t's nalne

氏名

学籍番号

第071202 号

AI^DREDZABINA1裁仏DMOKI{rARSupeNisors安井利明

指導教員

福本昌宏

Abstract

論文内容の要旨(博士)Title ofThesis

博士学位論文名

Study on operationalcharaC比dstics oflow power a血OspheHc presS山e microwave plasma
Spraymethod(低電力大気圧マイクロ波プラズマ溶射法の動作特性の研究)'ー(Approx.80o words)(要旨 1,200字程度)
Plasma spraying me壮10d is the most versatile coatin合 teclmique for 壮le deposition of hi帥 melti11g
Pohlt materials such as ceralnics and cemlet which is used in 壮le application ofwear, corrosion a11d heat
resistance.1t uses the heatsource generated by direct currenL radi0 丑'equency or microwave as the power

Source to meltthe spray particles which were injected ei壮ler axia11y or radia11y hlside the plasma plume
The accelerated particles wi11 C011ide and imphlged onto the surface of 壮le subS杜'ate to fabricate theCoating. conventional plasma spray method possesses very hi獣ltemperat11re plasma (above loooo K) at
high power(above 40 k圦1) which is very use負11to fabdcate hi獣lmelti11容PointmateHalcoating. However,
the excessive heat i11Put 6'om 壮le plasma may inauence in deterioration of matedal phase su'ucture hl
Some materialsuch as ceralnics a11d de部'aded some 丘111Ctions as we11 aS 壮le di缶Culw to fabdcate coating

Ont010w melting point subS訂'ate such as plastics, reshl a11d polymers. Here, the need ofusing low power
Plasma to reduce the heat hlput onto spray a11d subsh'ate mateHalis being focused 飢d microwave plasma
玉、is seen as a good candidate due to its stability hl wide ra11ge ofpresS山e a11d easy to be generated at low
Power. Microwave israrely been used asthe plasma powersource due to the unhlown mecha11ism a11d 壮leStabilization factor of the process. our research 即'oup has ma11aged to generate the plasma wi壮1
microwave at l.o k圦1' of power in atmosphedc condition a11d succeeded to fabdcate cu, Al a11d
hydroxyapatite coating. However,the mech飢ism 組ld charactedstics of壮le process is not studied weⅡ yet.
Thus, the main objective of 壮lis rese釘Ch is to study the operational ch釘acteristics of low power
microwave plasma spray me杜10d a11d its applicabiliw in reduci11g heat hlputtowards spray a11d subS訂'atematerials aS 廿le specialw of this teclmique. Moreover, the improvements a11d renovation of the spraydevice are also S加died 釘ld presented.
Firsay,the S加dy on operationalcharacteristics ofmicrowave plasma spray hlcompare to conventional
Plasma spray is conducted. Here,itis hl0町lthatthe microwave plasma spray method possessesthe heate伍Ciency comparable t0 廿le conventionalplasma spray which is atthe average of30 %.1he microwave
Plasma C卸 be generated 毎ld stabilized down to 03 kw aS 壮le resultreceived on plasma i即ition study.
The S加dy on plasma a11d spray particles behaviour ofmicrowave plasma spray showsthat 壮le plasma has
the average tempera加re ofover 400O K a11d particle veloci訂,, of B51Ws at 壮le maxim磁n paralneter.1he
Substrate temperature study shows that the suppression of temperature is able to be achieved for theapplication onto heat susceptible subsh'ates.

Ihe next study is worked on the applicabili切' ofmicrowave plasma spray hlreducing 廿le heat input
Onto substrate material. Here,the cr coating onto carbon fiberreinforced polymer (CFRP) was conducted.
The cFRp is focused in recent S加dies due to its properw ofhigh sh'engdlto wei獄ltratio but due to thePolymer mah'ix,the materialsurface S訂'uggles at wear and conosion resiS伽Ice in which the hard C11rome

Coating is crucialto overcome 壮lis disadva11tage. The conventional method for this coati11g producuon ish釘d C11rome plating. However,this method needs conh'olenvir01血ent dueto hazardous waste a11d slow inProduction which made the microwave plasma spraying me壮10d to be seen as the altemative method.

C11romium coating has been succesS丑111y deposited onto cFRp subsh'ate with coati11g microhardness
higherthan the average in hard C11rome plating at above HOO HV. The emergence ofcr oxides confmnedby x‑ray di缶'action atlalysis isthoU獣ltto be the factor conu'ibuting towardS 壮le increashlg hardness ofthe

Coating. chrome particles were mostly gathered onto the C釘bon fiber which appeared a丑er 廿le resin parts
Were melted by the plasma heat a11d 壮lis suggest that the mecha11ism of bonding is mostly by 壮lemech釘licalinterlocking.

The research iS 6】r仕lered on 壮le applicabili匂,, ofmicrowave plasma spraying method at suppressing
heatinput onto spray materials where 杜le S加dy on coating deposition ofTi02 With low heat e狂'ect onto
Spray matedalis conducted. Tita11ium dioxide is a photocatalyst materialfocused hlrecent studies because
Ofits ma即ificent properties where it possesses photocatalytic activity such asthe abiHぢ,to Nmove the air
P011Ution subS稔11Ce a11d deododzing 員lnction. Genera11y,壮le deposition method of a tita11ium dioxide
Coating is catried out by 廿le fixation oftita11iuln dioxide powder wi壮l a110rga11ic system binder but it wi11

Iet the de即'adation of壮le power6.11 Ca稔lytic reaction of a tita11ium dioxide. Therefore, themlal spray isthoU獣ltto be the altemative me廿10d but 壮lis method wi11induce 訂'a11Sfonnation 6'om a11a稔Se phase wi壮1
hi帥 Photocatalyst activiw to Ntile phase Mth low photocatalyst activiw due to excessive heat. As aresult,the maximum of83 % ofa11atase contentrate is achieved at optimU111Condition which suggeststhat'''气

the suppression of heat input onto spray matedals is succesS負111y obtained by using microwave plasma
Spray method. From the coating deposited by 99 % of rutile content rate ti伽lium dioxide powder,壮leanatase content rate increased inside the as‑sprayed coatmg proved that the nucleation of 田latase phase
Occuned during the spray. The a11atase content rate i11Side 壮le as・sprayed coathlg is increased with thedecrease ofsubS訂'ate temperat山e due to rapid cooling.
In fi缶I chapter, the research tasks a11d 員lture perspectives of low power microwave plasma spraydevice are discussed. Here, the research tasks are divided int0 壮lree categories which cover theimprovement in coating deposition, the device itself a11d enha11Cementthat should be made. some of壮lerequired optimizations of 血e cutrent device are particle velociり,, powder feeding method, a11telma

S訂'ucture, etc. For improvement of particle veloci切, electroma即etic phlch t1ⅡUst by ma即etic nozzle isConsidered a11d the exper血entations as we11 as the ma即etiC 6eld simulations are conducted. simulation
results help hl obtahling the stmcture of ma即etic nozzle 磁ld experhnentation Nsults show some
improvementin particle velociり,釘ld plasma temperature by 壮le use ofma即etic nozzle. However, due tothe elevated particle velociり,,is sti1110W,員lrther invest電ation should be made.

In condusion, this newly investigated me杜10d proved its specia1ち,, in low power plasma spray atextremely low power 釘ld its e缶Ciency to deposit coating wi壮Isuppress heat hlput e丘ect onto subsh'ate

飢d spray materials. Future research should be conducted to improve some ofits feature towards realizing
this method in 廿le mainsh'ealn ofthennalspray technique.