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'': Maintenance 

Instructions 

BUEHLER® 

ELECTROMET® 4~zk~liW '<-"' < :-/ -,- -,_ ,, 

POLISHER/ETCHER 
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Operation and Maintenance Instructions 

BUEHLER® ELECTROMET® 4 Polisher/Etcher 

Figure 1. ELECTROMET® 4 Polisher/Etcher 

Warranty 

Unpacking 

Assembly 

Electromet® 4 

This unit is guaranteed against defective material and workmanship for a 

period of two (2) years from date of receipt by customer. Warranty is void 

if inspection shows evidence of abuse. misuse or unauthorized repair. 

Warranty covers only replacement of defective materials. 

If, for any reason, this unit must be returned to our plant for warranty service, 

please apply for pripr authorization with shipping instructions, and include 

the following information: Customer Purchase Order Number, Buehler Ltd. 

Invoice Number and Date, Serial Number, and reason for return . 

Carefully unpack and check contents. If any components are missing or 

damaged, save the packing list and material and advise the carrier and 

Buehler Ltd. of the discrepancy . 

The ELECTROM El® 4 Polisher/Etcher is shipped as three units: the Power . 

source, the Polishing Cell and the Etching Cell. 

1 
Power Source 

Polishing Cell 

Etching Cell 

2 

The Power Source is shipped fully assembled. 

The Polishing Cell is shipped fully assembled except for the Support Post, 

Anode Arm and Cable which must be assembled and attached to the Cell 

Base. Figure 2 illustrates how various parts of the Polishing Cell are 

assembled. A set of five Masks is wrapped separately. 

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Figure 2. Polishing Cell Installation Detail 

The Etching Cell requires some minor assembly. First screw the Cell Post 

into the threaded hole in the Base; then slide the Arm Assembly over the 

Cell Post. Select either a Vertical or Horizontal Cathode, depending on the 

specimen to be etched. The Vertical Cathode is intended for mounted 

specimens and the Horizontal Cathode for those that are unmounted. For 

mounted specimens, electrical contact is made by means of the spring 

loaded Anode Rod which is part of the preassembled Arm Assembly. 

Unmounted specimens must be held by the Unmounted Specimen Clamp 

which is installed by sliding the open end of the Clamp Sleeve over the 

pointed end of the Anode Rod and tightening the thumb screw. 

Electromet® 4 
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Installation 

Electrical 

The ELECTROMET® 4 Polisher/Etcher should be installed in a convenient location near a chemical sink. It is advisable to place the 

Polishing Cell and/or the Etching Cell within a chemical fume hood 

on an adjacent table. For recommended ELECTROMET® 4 Polishing 

Cell layout, see Figure 3. For recommended ELECTROMET® 4 Etcher 

Cell layout, see Figure 4. 

POLISHING CELL (Figure 3): Connect the Polishing Cell Electrical Cable 

to the indicated outlet on the rear panel of the Power Source. Secure the 

connection by screwing the locking ring in a clockwise direction. Connect 

the temperature probe cable to the indicated outlet on the rear panel of 

the Power Source. Make sure that the Anode and Cathode Cables are 

plugged into their respective jacks in the Polishing Cell Base . 

ETCHING CELL (Figure 4): Clamp the Positive (red) Clip to the Anode 

Rod and the Negative (black) Clip to the Cathode. Insert the Electrical 

Jack into the indicated outlet on the rear panel of the Power Source . 

POWER SOURCE (Figure 3.and 4): Connect the Power Cord to an 

electrical outlet rated for the electrical service indicated on the Specification Plate on the rear panel. Position the white Selector Switch on the rear 

panel to the desired "Etch" or "Polish" mode. 

Polishing Cell Plumbing {Figure 3) 

The cooling system should be used at all times for reasons of safety as well 

as to assure uniform results. A significant increase in temperature could 

alter the results and in extreme cases produce explosive conditions. 

POWER ELECTRICAL CATHODE ANODE WATER 

SOURCE CABLE SUPPLY 

HOOD SINK 

AREA 

Figure 3. layout for ELECTROMET® 4 Power Source with Polishing Cell (Top View) 

Electromet® 4 3 
POWER 

SOURCE 

ETCHING 

CELL 

SINK 

HOOD 

AREA 

Figure 4. Layout for ELECTROMET® 4 Power Source with Etching Cell (Top View) 

To connect the cooling system, insert both hoses into the Plastic Hose 

Fittings on top of the Polishing Cell (Figure 3). Turn the plastic nuts 

clockwise to tighten. 

CAUTION Tighten with finger pressure only; do not use a wrench. 

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~ ) ~':'::~.-~P;llshlng ~ell Pre-operational Check (Figure 2) .,,{.:.:.,,,.....-· 

4 

When all the electrical and plumbing connections have been completed, 

operation should be checked, using water instead of an electrolyte. Fill 

the Electrolyte Tank with approximately 1 liter of water. Place the Tank on 

the Cell Base, allowing the Alignment Pins in the Cell Base to engage the 

Alignment Holes on the bottom of the Tank. Position the Pump Impeller 

in the bottom of the Electrolyte Tank. The powertul magnetic drive in the 

Cell Base wlll cause the Impeller to self-align. 

Put the Pump Body Assembly into the Electrolyte Tank so that the Lower 

Pump Housing encloses the Impeller. Select the desired mask and 

position it over the Cathode Tube opening. 

Press the Control On Button and the Pump On Button. Press the Pump 

Increase Button to increase the Pump speed. The water should rise to the 

top of the Cathode Tube and flow over the Mask. If the water does not 

rise, press the Pump Off Button and remove the Pump Body Assembly. 

Make sure the Impeller is free and return the Pump Body Assembly to the 

Electrolyte Tank. When normal operation is observed, remove the water 

from the tank. 

Electromet® 4 

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Polishing Theory 

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Electrolytic polishing produces a highly polished distortion-free sur1ace that 

is ideal for microscopic examination. Because abrasives are not used, there 

are no deformation layers to obscure the microstructure. Generally, 

pure metals and simple solid solution alloys such as stainless steel, 

aluminum. copper and titanium polish well. The more heterogeneous 

alloys, such as cast irons and most carbon steels, are much less responsive 

to electrolytic polishing. Electrolytically polished surfaces are also useful 

for surface sensitive tests where even small amounts of surface defo"rmation are unacceptable. 

Electrolytic polishing occurs when micro-elevations (scratches) on the 

specimen surface are removed by electrolytic dissolution. A surface that 

is uniformly abraded to a 600 grit or a finer finish is normally an aC<(eptable 

starting point. The specimen is the anode in the electrolytic cell formed by 

pumping an electrolyte (selected from Tables 1 and 2) through the cathode 

tube to the specimen surface. A specified direct current is applied across 

the specimen for a selected time interval. At the conclusion of the 

polishing, the specimen is removed, washed and dried. If the correct 

··conditions have been selected, a bright, smooth, highly polished area will 

be created. 

To achieve a complete circuit, electrical contact must be made with the 

back of the specimen. ~ the specimen is encapsulated, some special 

method of obtaining electrical contact may be required. Some suggested 

techniques are illustrated in Figure 5. 

b. 

d. 

a) Mount is cut so that the back of the specimen is 

exposed for direct contact with the current. 

b) A hole is drilled into the back of the mount so that a 

stainless screw or pin driven into the hole will contact 

the specimen. 

c) Wire contact is particularly useful for cold mounting and 

is reliable as long as a wire may be soldered, welded, 

or otherwise attached to the specimen. By extending 

the wire to the back surface, it may be attached to a 

contact block or reset itself as the electrical contact. 

d) A hole is drilled into the back of the mount and solder or 

fusable alloy is cast so that it contacts the back of the 

specimen. The hole should be large enough to allow the 

metal to flow easily into the hole. 

e) A tube, the approximate ID as the specimen, is placed 

on the specimen as it sits in the ram face in its down 

position. A conductive encapsulant is poured into the 

tube to a tly higher than the normal level. 

Glas phthalate is then poured around the 

outside of the tube, filling the remainder of the area. 

When the tube is withdrawn, there is a column of 

~ 

· uncured conducting epoxy in contact with the specimen 

within an outer non-conducting shell of glass-filled diallyl. 

The mount is then cured under the recommended heat 

and pressure, producing a mount that will conduct both 

heat and electricity. 

f) (Not Shown) specimen is mounted in conductive 

e. encapsulant. 

Figure 5. Methods for Making Conductive Mounts 

Electromet® 4 5 
In actual practice, it is usually necessary to make several attempts before 

the optimum conditions are established. Trial specimens should be run 

and the results microscopically examined. To correct problem conditions, 

refer to Table 4 "Trouble Shooting Chart," make the recommended 

adjustments, and perform new trial polishes until satisfactory results are 

obtained. Once acceptable conditions are achieved, repetitive results can 

be expected. 

Polishing Parameters 

Specific parameters which affect the polishing results and the controls 

involved are as follows: 

1. Electrolyte Composition (Operator Selection) 

2. Mask Size (Operator Selection) 

3. Electrolyte Flow Rate (Pump Section of 

Control Panel) • 

4. Voltage/Current (Polish/Etch Section of 

Control Panel) 

5. lime (lime Section of Control Panel) 

6. Temperature (Temperature LED ReadoutWater Supply) 

7. Specimen Preparation (Operator Technique) 

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Low Resistance Solutions 

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High Resistance Solutions / 

Volts------

Figure 6. Voltage-Current Density Curves 

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Depends on the specimen composition and 

thermal history. (See Tables 1 and 2) 

Select the smallest aperture to provide the surface 

area required. (See Table 3) 

Must be adequate to cover specimen surface 

without turbulence. 

Adjust to produce,current density required to obtain 

polishing (See Figure 6). Low values produce 

etching; high values produce gassing and heat. 

, Use the shortest time needed to produce 

acceptable results. Long times produce relief, 

pitting and artifacts. Short times produce 

inadequate polishing and/or scratches. 

Follow published recommendations. Keep 

electrolyte temperature constant to maintain 

uniform results and avoid unsafe conditions. 

Usually 600 grit is adequate; finer preparation is 

required in some cases. 

To determine the correct condilions for low resistance solutions, increase the voltage slowly from zero, The current will 

increase uniformly al first. When the current begins to fall 

even with a continued increase in voltage, the Polishing 

Plateau has been reached, The best polishing conditions are 

normally just beyond this point. 

Electrorriet® 4 
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Etc~ing 

Operation 

Etc~ing with the ELECTROMET® 4 unit may be accomplished either in 

the Polishing or the Etching Cell. Some specimen materials will etch in 

the same electrolyte used for polishing. In such instances, etching may 

be done in the Polishing Cell, either concurrently or as an independent 

operation. For concurrent polishing-etching, set both the polish and etch 

· times as indicated above. When the normal polishing cycle is completed, 

the etching cycle will begin automatically. 

For independent etching in the Polishing Cell, set the Etch Time as 

indicated above except set the Polish Time to zero and do not press the 

Polish On Button. Instead press the Etch On Button. 

The Etching Cell should be used when an electrolyte other than that used 

for polishing is desirable. To perform external etching, makethe necessary 

connections described under installation. Make sure the Etch/Polish 

Selector Switch on the rear panel of the Power Source is depressed 

toward Etching Cell Socket. Select an appropriate electrolyte from Table 

5 and fill the Electrolyte Container about 3/4 full. When etching a mounted 

specimen, place the specimen on the bottom of the Electrolyte Container, 

polished side up. Lower the Arm Assembly so that the point of the Anode 

Rod contacts the specimen, preferably near the center. Adjust the height 

of the Vertical Cathode, if required, so that it is fully immersed, but not in 

contact with the specimen. Unmounted specimens should be secured in 

the Unmounted Specimen Clamp, polished side down. Place the Horizontal Cathode in the electrolyte and lower the Arm Assembly until the 

polished face of the specimen is barely covered by electrolyte. 

Electrolytic etching is similar to electropolishing except that ,it occurs at a 

lower voltage (see Figure 6) and does not usu~lly require a continual flow 

of electrolyte. Etching normally occurs in the 3-5 volt D.C. range, as 

monitored by Volt LED Display. 

The Stainless Steel Cathode is used for most specimens but, in some 

applications, other materials may be required. Consult Table 5 for recommended cathode materials . 

Polishing Cell (Figure 7) 

Electromet@ 4 

The Polishing Cell can be used for polishing, etching or a combination of 

both. 

• Fill Electrolyte Tank. All Cooling Coils should be submerged. 

• Use acid resistant tongs to positionthe Impeller in the Tank. 

• Place Pump Assembly in the Tank so that the Lower Pump Housing 

encloses the Impeller. 

• Select and position a Mask. NEVER OPERATE WITHOUT A MASK . 

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TEMP. "C 

ELECTROMET® 

4 

ELECTRDPDLISHER POWER SUPPLY 

CONTROL 

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v~ OFF 

A BUEHL.ER 1.'l'D ... I.AKE DUJFF, II. .. 60044 w USA 

Figure 7. Control Panel 

NOTE 

NOTE 

8 

Press Control On Button. LED will light. 

• Press the Pump On Button and adjust the pump speed, using the 

Pump Increase and Decrease Buttons, so the electrolyte will rise to fill 

Mask opening and overflow slightly. 

• Press the Pump Off Button but do not change the speed setting. 

• Place specimen, face down, on Mask. 

• Slide Anode Arm down to make electrical contact with back of 

specimen. 

• If Polishing is desired, press Time Polish Button. LED will light. Set 

Time LED Display for the desired polish time using the lime Increase 

and Decrease Buttons. The lime Clear Button will reset the polish time 

to zero. 

If the unit is run for a long period of time without cooling, the Fault 

Temperature LED will begin to blink at approximately 46° - 51° C, warning 

the operator to cool the electrolyte. If the operator does not cool the 

electrolyte, the temperature will generally rise and the Fault Indicator will 

stay on at 51° - 56° C and the unit will shut down. When the temperature 

falls below 45° C, the unit can be restarted. 

• H Etching is desired, press lime Etch Button. LED will light. Set lime LED 

Display for the desired etch time using the lime Decrease and Increase 

Buttons. The lime Clear Button will reset the etch time to zero. 

If Etching is not desired, press the lime Etch Button and clear the etch 

time pressing the lime Clear Button. If the etch time is not cleared to zero, 

the unit will automatically go into etch after polishing cycle is completed. 

•· Set the Volts LED Display· to the desired voltage using the Volts 

Increase and Decrease Buttons. 

Electromet® 4 
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NOTE 

NOTE 

Etching Cell (Figure 7) 

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Electromet® 4 

• Press and hold the Load Test Button. Adjust the Volts Increase and 

Decrease Buttons until the recommended current density or until voltage/current plateau is reached, as monitored on the AM PS LED Digital 

Display and Bar Graph. The Bar Graph will detect he current plateau 

since it is not indicating instantaneous current as is the Digital Display. 

If the unit is run at a current too high for the specimen, the Fault Load LED 

will light and the unit will shut down. When the load is reduced, press the 

Fault Reset Button to restart the cycle. 

• If polishing was set, press the Polish On Button to start the cycle. The 

LED will light. When polishing cycle is over, the LED light will extinguish. If Etching was set, the Etch LED will light and the unit will begin 

the etching cycle. 

• If ·etching only was set, press the Etch On Button to start the cycle. 

The LED will light. When the etching cycle is over, the LED light will 

extinguish. 

During the cycle, the Time LED will count down the cycle time to zero. 

• During the operating cycle, observe the Electrolyte Temperature LED 

Readout. This displays the actual temperature of the electrolyte. 

At the end of the cycle, press the Pump Off Button, lift the Anode Arm, 

and remove the specil)1en with acid resistant tongs. NEVER REMOVE 

SAMPLE WHILE POLISHING OR ETCHING IS IN PROGRESS. 

• Wash specimen thoroughly, dry, and examine. 

• -Determine nominal composition of specimen to be etched. 

• Select suitable electrolyte and fill Container 3/4 full. 

• Place mounted specimen, face up, on the bottom of container, u~ing 

tongs. Lower Anode Rod to make contact with specimen surface. 

• Lower Unmounted Specimen Clamp until polished specimen face is 

barely covered by electrolyte. 

• Press Time Etch Button. LED will light. 

• Set Time LED Display for the desired etch time using . the Time 

Increase and Decrease Buttons. The Time Clear Button will reset the 

etch time to zero. 

Set the Volts LED Display to the desired voltage using the Volts 

Increase and Decrease Buttons. 

• Press and hold the Load Test Button. Adjust the Volts Increase and 

Decrease Buttons until the recommended current density or until 

voltage/current plateau is reached, as monitored on the amps LED 

Digital Display and Bar Graph. 

9 
NOTE 

NOTE 

Maintenance 

General Specifications 

If the unit is run at a current too high for the specimen, the Fault Load LED 

will light and the unit will shut down. When the load is reduced, press the 

Fault Reset Button to start the cycle over. 

• Press the Etch On Button to start the cycle. The LED will light. 

During the cycle, the lime LED will count dowr:i the cycle time to zero. 

• When etching cycle is over, the LED light will extinguish. 

• Raise Arm Assembly, remove specimen with tongs, wash and dry. 

After use, mixed electrolytes should be returned to the storage bottle. If 

the electrolyte is noticeably discolored, it should be discarded according 

to local guidelines for chemical disposal. Wash the Electrolyte Tank and 

Pump Assembly thoroughly after each use. Wipe the Cell Base surfaces 

with a sponge or damp cloth and wipe dry. The Power Source should be 

wiped off periodically or immediately after having been splashed by 

electrolytes or component chemicals. 

ELECTROMET 4 tested in our laboratory, background noise level 

45.6 dBA. 

Precautions Regardl ng the Use of Electrolytes 

NOTE 

10 

• Mix all electrolytes with extreme care, using proven formulations and 

recommended laboratory practice-do not experiment. 

• Never pour solvent liquid into concentrated acids, particularly sulfuric 

acid. 

• Never allow re-used electrolytes to become too concentrated due to 

normal evaporation. Keep loosely covered with pop-off lids. Maintain 

the original concentration by adding additional solvent' liquid if necessary. Concentration is particularly important when using electrolytes 

containing perchloric or nitric acid. 

• Keep all storage bottles identified as to contents and recommended 

use. 

• Dispose of disoolored electrolytes according to corporate, or local 

guidelines for waste chemicals. 

• Store electrolytes under proper temperature and safety conditions. 

Maintain the recommended operation temperature for the electrolyte. 

Elevated temperatures increase the risk of explosion. 

Electromet® 4 
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Figure 11. Parts Diagram for ELECTROME 4 Polisher/Etcher Polishing Cell 

14 Electromet® 4 
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ELECTROMEl® 4 Polisher/Etcher Polishing Cell Parts List 

PART PART 

REF NO. QTY DESCRIPTION REF NO. QTY DESCRIP'rlON 

1 18328022 1 Pump Chamber Assembly 21 R-1663PPH 8 Screw 10-32 1/4 In Cr Pn 

2 1760S026 1 Temperature Probe Assembly HdSS 

3 17328021 1 5132 Inch Hex Wr Cd Pl 22 R-0612LW 4 Lock Washer #10 SS 

4 R-7324 1 Stirring Bar 23 R-0585 1 lie.Strap .10 X4 In 

5 1732S011 1 Tank 24 R-8370 1 Mount Cable lie 

6 R-8039 2 Lockwasher 1/4 In External 26 R-7042 2 Molex Pin Male 

7 R-7241 1 Jack, Phono Red 27 R-7045 1 Molex Plug 2 Connector 

8 18328010 1 Housing - Cell Pump 28 R-7491 4 Screw 6-32 3/8 In Cr Pan 

9 1832$016 1 Nameplate Electromet 4 Cell HdSS 

10 R-1314 1 Screw Set 5/16-18 5/16 In SS 29 R-0605LWE 1 Washer, Lock 

11 1700$509 1 Magnet Drive Assembly 31 R-1303 2 Screw Set 1/4-20 1/4 In SS 

12 18328013 1 Plate - Motor Mount 32 R-7242 1 Jack, Banana Black 

13 18328011 1 Motor 1/30 HP DC 90V 33 18328018 1 Post, Support 

14 R-8592 2 Terminal .187 Flag Fully Ins 34 18328019 2 Spacer 112 X .194 X 1 

15 R-8456 2 M/F Piggyback Disconnect 35 R-8004 2 Screw 10-32 1-3/4 In Skt Hd 

16 R-7299 1 Resistor 750 Ohm 20W 36 17328052 1 Anode Assembly 

17 1832S014 1 Cover - Bottom 37 17328032 1 Umbilical Cord and Plug 

18 18328026 1 Specification Plate 38 R-8635 1 Bushing, Cord 

19 R-8732 4 Screw, St. 8-32 X 112 Ph Pn 39 18328020 2 Pin - Shoulder 10/32 

HdSSPa 40 R-0414 12 Wire #16 Black Stranded 

20 R-2700 4 Bumper Alt #18 - Mounting Feet 

Electromet@ 4 15 
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Figure 12. Parts Diagram for ELECTROME 4 Polisher/Etcher Power Supply 

16 Electromet® 4 
ELECTROMET® 4 Polisher/Etcher Power Supply Parts List 

PART PART 

REF. NO. QTY. DESCRIPTION REF. NO. QTY. DESCRIPTION 

1 17906062 1 Bi-Lingual Caution Plate 28 1760S056 1 Specification Plate (100 V)"CE 

2 R-8550 2 Screw #2-56 X 112 CR Pan Hd SS 17608057 1 Specification Plate (115 V) CE 

(100 V) 1760S058 1 Specification Plate (220 V) CE 

3 17606040 Switch Plate 50/60 Hz 29 R-8321 2 Screw 4-40 518 In. Cr Flat Hd 

(100 V) 30 R-0603LW 6 Lockwasher #4 Stainless Steel 

4 . R-1625 2 Screw 6-32 3/8 In Sit Rd Hd SS 31 R-8086 4 Screw 4-40 1/2 In Cr Pan 

5 17606053 2 Fuse Plate MDX 1-1/4 HdSS 

6 17318010 1 Selector Plate 32 R-7705 3 Fuse 1.25A250V 

7 R-7290 1 Switch 4PDT 33 1305S17 2 Fuse Post 

8 17608010 1 Cabinet Upper 34 R-8078 1 Screw 10-32 718 In Cr Pan 

9 17606042 1 Nameplate Electromet 4 HdSS 

10 R-8571 19 Button-Switch Control Panel 35 R-0612LWE 3 Lock Washer #10 Ext SS 

11 17606024 1 . Power SUpply Assembly- 36 R-0612 3 Locknut 10-32 Hex SS . 

Elect. (115 V) 37 17028017 1 Wire Ground 40 In 

17608035 Power Supply Assembly 38 · R-0539 1 Terminal #10 Ring 16-14 NIT 

Elect. (220 V) 39 R-8544 1 Connector, Male Tab .187 

12 R-7482 1 Clip, Component 1/2 Dia 40 1180S72 8 Nut 16-32 KEPS 

13 R-0614 4 Nut 1/4-20 Hex 41 17606016 1 PCB Operators Control Panel 

14 R-0615LW 4 Lockwasher 114 In SS 42 R-8572 8 Spacet 6-32 .25 Dia. x 

15 18328015 4 Spacer .250 ID X .500 Long .420 Long 

16 R-7281 1 Etch Jack Isolated 43 R-8166 4 Retaining Ring Ext .250 

17 17606041 1 Label Elect. Component 44 1180S90 2 Nut 2-56 Hex (100 V) 

18 R-0603 6 Nut 4-40 Hex SS 45 1180$89 2 Lockwasher #2 ( 100 V) 

19 17608011 1 Cabinet Lower 46 R-8546 1 SWitch DPDT Slide (100 V) 

20 R-7886 4 Bumper, Rubber 17518045 1 Transformer 100V -125V 

21 R-2408 4 Screw 114-20 1-3/4 In Hex 10Amp(100V)* 

HdSS 55008044 3 Pin-Connector (100 V)* 

22 R-8465 4 Screw 10-16 x 1 Hex Hd SS R-16666PPH 4 Screw 10-32 1/2 In CR Pan 

23 17318022 1 Power Cord ( 115 V) Hd SS (100 V)* 

12708078 1 Power Cord (220 V) R-8458 Connector 3 Pin Mole 

24 R-4536 1 Bushing-Cord ( 115 V) (100 V)* 

R-4535 1 Bushing Cord (220 V) R-7693 24 Wire #22 Stranded Black 

25 1751$039 1 Fuse Plate 15 MDA (115 V) (100 V)* 

17608054 1 Fuse Plate MOAB (220 V) R-7692 24 Wire #22 Stranded White 

26 R-7409 2 Fuse 15Amp (115 V) (100 V)* 

R-4554 2 Fuse 8 Amp (220 V) R-7691 24 Wire 22 Ga Stranded White 

27 R-8347 1 Fused Switch 20/15/A (100 V)* 

120/250V 

•Not Shown 

I 

, ... 

• f 

I ' 

l 

I 

I 

Electromet® 4 17 
Table 1. Suggested Electrolytes for Metals and Generally Their Alloys* 

Metal or Alloy Electrolyte No. Metal or Alloy Electrolyte No. 

Aluminum 1·1, l-2, 1·4, 1·5, 1-6, 1·8, 1-10 Molybdenum 1-7,IV-4, IV·7, Vl-20 

11-3,111·7,IV-6 Nickel-chromium 11-4, Vlll·1 Aluminum·silicon alloys 1-6, 1-8 

Nickel l-4, 11-4, IV-2. Vlll-1 Antimony 11-4 

Beryllium 1-4 Silicon Vll·5 

Bismuth Vl-18, Vl-25 Silver 111-7, Vll-2, Vll-3,Vll-1 Cadmium 111-4 Steel, austen~ic, l· 1, 1-2. f.3, l-4, 1·5, 11· 1, 11-2. Cast iron 1-4, 11-1 

Chromium 11-1, Vlll-1 stainless, and super 11-3, 111-3, 111·6. 111· 11, 

Cobalt 1·5, 11-3, 111·1, 111·4, Vll1'1 alloys IV-1, IV-2, IV-3, IV-5, IV-6, 

Copper 111·2. 111·3, 111-4.111-5, 111·10, V-1, Vf. 1, Vl-2, Vl-3, Vl-4, 

Vlll-1 Vl-7, Vf.8, Vl-9, Vl·10 

Copper-zinc alloys llf.3, 111-4, 111-5, lll-10, V-2 Vl·11, Vf.13, Vl-15, Vl-16, 

Vlll-1 Vl·17, Vlll-1 

Copper-tin alloys lll-10, Vl-5, Vl-6, Vlll-1 Steel, carbon and alloy 1-1, 1-2. 1-4, 1-5. 11· 1, 11·2, 11-3. 

Copper-nickel alloys 111-3. 111·10, Vlll-1 11·5, 111-6, Vl·3. Vl-11 

Germanium 1-9 Tantalum Vl-12 

Gold Vll-1 nn 1-4. Vl-5, Vl-6, Vll-6 

Hafnium Vll-11 litanium 1-4,1-9, 11-1, 11-2, 11-3 

Iron, pure 1·5, 11·1, IV-2, IV-3 Tungsten Vll-4, Vll-5 

lron·silloon alloys '1-5, 1-6, l·S. 11-5 Uranium 1-4, 1-7, 11-1, 11-2.11·3, lll-ll, 

Iron-copper alloys 111-3, 111-4 111-13 

Iron-nickel alloys 1-5, 11-1, 11-2, 11-4, IV-3, VI 11-1 Vanadium 1-9 

Lead 1-1, 1-5, 11-4, Vll-5 Zinc 1-1, l-5, 111·12, V-2. Vl-14, 

Magnesium 1·1, 111·7, 111·12, Vl-19 Vl·23. Vll-6, Vlll·1 

Manganese 111-9 Zirconium 1-4, 1-7, 1-9, 11·2, Vl-24 

Table 2. Electrolytes for Electropolishing* 

' Cla• Use Formula Cell Voltage Time Remark& 

1: Group I (electrolytes Composed of Perchlorlc Acid and Alcohol With or Without Organic Additional , . 

I 1·1 Al and Al alloY.S with less than ethanol (95 percent) 800ml 30to80 151o60s 

2percent SI distilled water 140ml 

perchloric acid (60 percent) 60ml 

steels-carbon, alloy, stainless 351065 151060 s Pb, Pb-Sn, Pb-Sn-Cd, Pb·Sn-Sb 121035 15 to60 s 

Zn, Zn-Sn-Fe, Zn·Al-Cu 201060 

Mg and high Mg alloys nickel calhodf! 

1-2 stainless steel and aluminum ethanol (95 percent) 800ml 35to80 15to60s,. 

perchloric acid (60 percent) 200ml 

I 1-3 stainless steel ethanol (95 percent) 940ml 301o45 151o60s 

perchloric acid (65 percent) 60ml ;1 l-4 steel, cast Iron, Al, Al alloys. ethanol (95 percent) 700ml 301065 151o60s one of the best formulas for 

Ii 

NI, Sn. Ag. Be, TI, Zr, U. 2-butoxy ethanol 100ml universal use 

heat-resisting alloys perchloric acid (30 percent) 200ml 

1-5 steefs--illainless, alloy, high: ethanol (95 percent) 700ml 15to50 151o60s universal electrolyte· comparable 

:~ ! 

speed; Fe, Al, Zr. Pb glycerin 100ml lo 1-4 

perchlorlc acid (30 percent) 200ml 

l-6 Al, A~SI alloys ethanol (95 percent) 760ml 35to60 15to60 s particulary good wtth Al-Si 

diethyl ether 190ml alloys 

perchloric acid (30 percent) 50ml 

1·7 Mo, TI, Zr, U-Zr alloy methanol (absolute) 600ml 6010150 5to 30 s 

2-butoxy ethanol 370ml " perchloric acid (60 percent) 30ml 

1-8 Af.Si alloys methanol (a!Jsolute) 840ml 50to 100 5to60s 

glycerin 125ml 

perchloric acid (65 percent) 35ml 

1-9 vanadium methanol (absolute) 590ml 30 3• th-second cycles repealed at 2-butoxy ethanol 350ml lea11t seven times lo prevent 

perchloric acid (65 percent) 60ml heating 

.germanium 25to35 30to60s 

titanium 581066 45·· polish only 

zirconium 70to75 15 s polish and etch simuftaneously 

1-10 aluminum methane! (absolute) 950ml 30to60 15to60s 

nitric acid 15ml 

perchloric acid (60 percent) 50ml 

*Reprinted by permissio·n of the American Society for Testing and Materials, Copyright. ' 

18 Electromet® 4 

"" 
I 

Table 2. Electrolytes for Electropolishing (Continued) 

Claaa u.e Formula Cell Voltage Time Remark11 

Group II (Electrolyte& Compoeed ol Perchlorlc Acid and Gl11cl11I Acetic.Acid In Varying Proportfona) 

11-1 Cr, Ti,Zr,U acetic acid (glacial) 940ml 20to60 1to5mi'ii good general-purpose 

Fe, steel caibon, alloy, stain· perchloric acid (60 percent) 60ml electrolyte 

less 

11·2 Zr.TI, U, steel-carbon and acetic acid (glacial) 900ml 12to70 0.5to2min 

alloy perchloric acid (60 percent) 100ml 

I 11-3 U, Zr, TI, Al, steel-carbon and acetic acid (glacial) 800ml 4010100 1to15 min 

alloy perchloric acid (60 percent) 200ml 

114 Ni, Pb, Pb-Sb alloys acetic acid (glacial) 700ml 40to 100 1 !o5min 

perchloric acid (60 percent) 300ml 

11-5 3 percent Si-Fe acetic acid (glacial) 650ml 5min O.OOA/crrf 

I perchlorlo acid (60 percent) 350ml 

Group Ill (Electrolytes compoeed of Phoaphorlc Acid ln Water or Organic Solvent) 

111-1 cobalt phosphoric acid (85 percent) 1000ml 12 3!o5min 

111-2 pure copper distHled waler 175ml 1.0to1.6 101040 min copper cathode 

I phosphoric acid (85 percent) 825ml 

111-3 stainless, brass, Cu and Cu al- water 300ml 1.5 to 1.8 51015 min copper cathode 

Joys except Sn bronze phosphoric acid (85 percent) 700ml 

111·4 alpha or alpha plus beta brass, waler 600ml 1 to2 1to15 min copper or stainless steel cathode 

Cu-Fe, Cu-Co, Co, Cd phosphoric acid (85 percent) 400ml 

I 111·5 Cu, Cu-Zn water 1000ml 1 to2 10min OOjlper cathode 

pyrophosphoric acid 580g 

111-6 steel diethylene glycol monoethyl ether 500ml 5to20 5to15min 120F 

phosphoric acid (85 percent) 500ml 

111-7 Al,Ag,Mg water 200ml 25to30 4to6min aluminum cathode, 100to 110 F 

I ethanol (95 percent) 380ml 

phosphoric acid (85 percent) 400ml 

111·8 uranium ethanol (absolute) 300ml 

glycerin (q>) 300ml 

phosphoric acid (85 percent) 300ml 

• 

111·9 Mn, Mn-Cu alloys ethanol (95 percent) 500ml 18 

glycerin 250ml 

phosphoric acid (85 percent) 250ml 

111-10 Cu and Cu-base alloys distilled waler 500ml 1 to5mln 

ethane! (95 percent) 250ml 

phosphoric acid (85 percent) 250ml 

I 11~11 stainless steel ethanol (absolute), to 1 liter 10min good for all austenitlc heat re· 

pyrophosphoric acid 400g sislant alloys, 100 F plus 

11~'12 Mg· Zn ethanol (95 percent) 625ml 1.5to2.5 3to30mln 

phosphoric acid (85 percent) 375ml 

111-13 ·uranium ethanol (95 percent) 445ml 18to20 5to15min 0.03A/crrf 

I ethylene glycol 275ml 

phosphoric acid (85 percent) 275ml 

~roup IV (Eleotrolylea Composed of Sulfuric Acid In Water or Organic Solvent) 

IV-1 stainless steel water 250ml 1.5to6 1 lo2min 

I sulturic acid 750ml 

IV-2 stainless steel, Fe. Ni water 400ml 1.5to6 2to6min 

sulturic acid 600ml 

IV-3 stalnless steel, Fe. Ni, Mo water 750ml 1.5106 2to 10 min particularly good for sintered 

suffuric acid 25om1 Mo-0.3 to 1 min Mo. Ma-32 to 80 F 

I IV4 molybdenum water 900ml 1.5to6 0.3to2 min particularly good for sintered 

sulturic acid 100ml Mo. 32 toBOF 

IV-5 stainless steel water 70ml 1.5to6 0.5 to5 min 

glycerin 200ml 

sulturic acid 720ml 

I IV-6 stainless steel, aluminum water 220ml 1.Sto12 1to20 min 

glycerin 200ml 

suffuric acid 580ml 

IV-7 molybdenum methanol (absolute) 875ml 6to 18 0.5to1.5 min 32to80F 

• suffuric acid 125ml 

I Group V (Electrolytes Compoeed ol Chromic Aoki In Water) 

V-1 stainless steel water 830ml 1.5to9 2to 10 min 

chromic aCid 620g 

V-2 Zn, brass waler 830ml 1.5to12 10to60s 

I chromic acid 1709 

I '! 

~ 

I Elebtromet® 4 '··· 19 
Table 2. Electrolytes for Electropolishing (Continued) 

ClllM Use Formula CeHVollllge Time Remarks 

Group VI (Mixed Acids or Salta In Water or Organic Solution) 

Vl-1 stainless steel phosphoric acid (85 percent) 600ml 

suffurio acid 400ml 

Vl-2 stainless steel water 150ml 2nln 0.3A/cm2 

phosphoric acid (85 percent) 300ml 

suffuric acid 550ml 

Vl-3 stainless and alloy steel waler 240ml 21o10nm 0.1 lo02A/cm2 

phosphoric acid (85 percent) 420ml 

s uffuric acid ~Oml 

Vl-4 stainless steel waler 330ml 1 min OSJSM:J 

phosphoric acid (85 percent) 550ml 

suffurlc acid 120ml 

Vl-5 bronze (to 9 percent Sn) water 450ml 1lo5min 0.1~ phosphoric acid (85 percent) 390ml 

suffuric acid 160ml 

Vl-6 bronze (lo 6 percent Sn) water 330ml 1to5min 0.1 Alcm2 

phosphoric acid (85 percent) 560ml 4' sufuric acid 90ml 

Vl-7 steel waler 140ml 1 to5min 11o5Alclii2, 100 F plus 

glycerin 100ml 

phosphoric acid (85 percent) 430ml 

suHuric acid 330mt 

Vl-8 stainless steel water 200ml 5min 1 A!cm2, 80 to 120 F 

glycerin 590ml 

phosphoric acid (85 percent) 100mt 

suffurio acid 110ml 

Vl-9 stainless steel water 260ml 30min 0.6 Alom2, BO lo 120 F 

chromic acid 1759 

phosphoric acid (85 percent) 175ml 

suffuric acid 580ml 

Vl-10 stainless steel water 175ml 60min 0.5 A/cm2, BO to 120 F 

chromic acid 105g 

phosphoric acid (85 percent) 460ml 

suffuric acid 390ml t Vl-11 stainless and alloy steel water 240ml 5to60 min 0.5 lo A1cm2, 100 to 130 F 

chromic acid 809 

phosphoric acid (85 percent) 650ml 

suffuric acid 130ml 

Vl-12 tantalum hydrofluoric acid 100ml 9min Graphite cathode, 0.1 A/cm2, 

suffuric acid 900ml 90to100F 

Vl-13 stainless steel water 210ml 5min 0.5 Alcm2, 70 to 120 F 

hydrofluoric acid 180ml 

suffuric acid 610ml 

Vl-14 zinc water eooml 0.002A/cm2, 70to 100 F 

chromic acid 1009 

suffuric: acid 46ml 

sodium dichromate 3109 

acetic acid (glacial) 96ml 

Vl-15 stainless steel hydrogen peroxide (30 perc:ent) 260ml 5min 0.5 Alom2 (Caution) Dangerous 

(Caution) 

hydrofluoric acid 240ml 

suffuric acid 500ml 

Vl-16 stainless steel waler 520ml 1to4min 0.08 to 0.3 A/cm2 

hydrofluoric acid 80ml 

suffuric acid 400ml 

Vl-17 stainless steel water 60.0ml 

chromic acid 180g 

nitric acid 60m1 

hydrochloric acid 3m1 

suffuric acid 240ml 

Vl-18 bismuth glycerin 750ml 12 1to5min 0.5 ±A!cm2 (Caution) This mixacetic acid (glacial) 125ml ture will decompose vigornttrlc acid 125ml ously after a short time. Do 

not try to keep. 

Vl-1g magnesium ethylene glycol monoethyl ether 900ml 50to60 10to30 s Bath should be stirred. Cool 

hydrochloric acid 100ml cracked ioe below 35 F 

Vl·20 molybdemun, sintered and cast methanol (absolute) 685m1 19to35 20to35s Mix slowly. Heat is developed. 

hydrochloric acid 225ml Avoid contamination w~h 

sutturic acid 90ml water Below 35 F 

Vl-21 titanium ethanol (95 percent) 900ml 30to60 1to6min (Caution) Anhydrous aluminum 

n·butyl alcohol 100ml chloride is extremely dangeraluminum chloride (anhydrous) 609 ous to handle 

(add very slowly) (Caution) 

zinc chloride (anhydrous) 250g 

Q 

20 Electromet® 4 
~ Table 2. Electrolytes for Electropolishing {Continued) 

I Claaa Uae Formula Cell Voltage Time Remarks 

Group VI (Mixed Acids or Satts in Water or Organic Solution) 

Vl-22 uranium acetic acld (glacial) 750ml 80 5to30 min The chromic acid is dissolved in 

distilled waler 210m1 the waler before adding to chromic acid 180g the acetic acid. Below 35 F 

V~23 pure zinc ethanol (95 percent) 720ml 25to40 0.5to3 min (Caution) Anhydrous aluminum 

aluminum chloride (anhydrous) 50g chloride is extrehlefy danger-

(Caution) ous to handle. Below 60 F 

zinc chloride (anhydrous) 225g 

distilled waler 160ml 

n-butyl alcohol 80ml 

Vl-24 zirconium. Polish and etch glycerin (Caution) 870ml 9to 12 1to10 min (Caution) will decompose on 

simultaneously hydrofluoric acid 43ml standing, dangerous if kept 

nitric acid 87ml too long 

Vl-25 bismuth saturated solution K1 in distilled 980ml 7 30s polish 30 s but allow to remain water in electrolyte until brown film 

hydrochloric acid 20ml is dissolved 

Group VII (Alkaline Electrolytes) 

Vll-1 gold water lo 1000ml 7.5 2to4 min graphite cathode 

potassium cyanide 80g 

potassium carbonate 40g 

gold chloride 50g 

Vll-2 silver water to 1000 ml 2.5 To 1 min graphite cathode 

sodium cyanide 100g 

potassium ferrocyanide 100g 

Vll-3 silver water lo 1000ml T09min graphite cathode, 0.003 to 0.009 

potassium cyanide 400g A/err?-

silver cyanide 280g 

potassium dichromate 280g 

VU.4. tungsten water to 1000 ml 10min graphite cathode, 0.09 A/cm2, I trisodium phosphate 160g 1001o 120 F 

Vll-5 tungsten, lead water to 1000 ml Bio 10 min graphite cathode, 0.03 to 0.06 

sodium hydroxide 100g A/cm2 

Vll-6 zinc.tin water to 1000-ml 2106 15min acopper cathode, 0.1 to 0.2 Alcm2 

potassium hydroxide 200g 

Group VIII (Mixture of Methyl Alcohol and Nttrlc Acid) • Vlll-1 Ni, Cu, Zn, Mone!, brass, Ni- methanol (absolute) 660ml 40to70 10to60 s very widely useful but dangerous 

I chrome, stainless steel nitric acid 330ml 

I Table 3. Mask Sizes and Orifice Areas 

Mask Orifice Dia. Area 

A 0.36" 0.10 ln2 

0.91 cm 0.65cm2 

B 0.50" 0.20 ln2 

1.27 cm 1.27 cm2 

c 0.71" 0.40 ln2 

1.80 cm 2.54 cm2 

D 0.87" 0.59 ln2 

2.21 cm 3.84 cm2 

• 0.35 ln2 E 0.59" 

~ 1.50 cm 2.25 cm2 

• Square orifice 

Electromet® 4 21 
22 Electromet® 4 
Table 5. Recommendations for Electrolytic Etching 

Metal Bath Con-position erature Electrical Cathode Time Rematks 

•F Condilions Material 

Aluminum 210 parts orthaphosphoric acid 

45 parts amyl alcohol 

24 75 0. 75 to 1.2 amp/sq cm Stainless 

steel 

1.5 to 2.5 min For 2S & 3S Al. 

65 parts distilled waler 

Brass 3 parts orthophosphoric acid 16 to 27 60to80 O.o1 amp/sq cm Copper Few Alpha and beta 

5 parts water seconds brass 

Brass 4 parts orthophosphoric acid 24 75 0.008 to 0.012 an-p/sq an CoPPer Few Alpha brass. 

6 parts water seconds. 

Bronze 67 parts orthophospohric acid 24 75 O.Bvolt Copper 30sec For bronze containing 

10 parts suffuric acid (cone) uplo6%Sn. 

23 parts distilled waler 

Bronze 47 parts orthophosphoric acid 24 75 O.Bvolt Copper 30sec For bronze eontaining 

20 parts suffuric acid (cone) more lhan 6% Sn. 

33 parts distilled waler 

Cobalt Orthophosphoric acid 24 75 1.2volts Stainless Few Agitate bath. 

steel seconds 

Cobalt and 5 parts hydroehloric acid 24 75 6volls Plalinum 10sec Calhode distance, 

Alloys 1 to 10 parts chromic acid (10%) or stain- 3/4 to 1 in. 

less steel 

Copper 2 parts orthophosphori<rncid 24 75 O.Bvolt Copper 30see Suitable for alloys 

1 part distilled waler except tin bronzes. 

Germanium Oxalic acid 24 75 4to 6volts Stainless 10 to 20sec Grain boundary etch. 

(100g/1 waler) steel 

Molybdenum Oxalic acid (0.5%) 52 125 3to 9volts Stainless 5sec 

steel 

Molybdenum Sodium hydroxide (10%) 24 75 1.5 to 3volts Platinum 1 to5sec 

or slainless steel 

Nickel and Chromic acid (10%) 24 75 1.5volts Platinum 1to3sec 

Alloys or stainless steel 

Nickel and 2 parts nitric acid (cone) 24 75 1.5volts Stainless 20to60sec Good for nickel alloys. 

Alloys 1 part glacial acetic acid steel Excellent for grain size. 

17 parts water 

Nickel and Oxalic acid (10%) 24 75 1.5 to 6volts Platinum 15to30sec Good for lnconel. 

Alloys 

Nickel and SuHuric acid (3%) 24 75 6volts Stainless 5 to30sec Shows carbides and • Alloys steel grain boundaries. 

lnconel and nickelchromium alloys. 

Silver Alloys Citric acid (10%) 24 75 611olts Stainless 15sec General use. 

plus few drops nitric acid 0.01 a.mp/sq cm steel 

Steel 2 g picric acid 24 75 6volls Stainless 30sec Low·alloy steel. 

25 g sodium hydroxide steel Stains iron carbides. 

100 ml distilled waler 

Steel Chromic acid (10%) 24 75 ·3 volls Stainless Variable Austenttic or ferritlc 

steel slainless. Attacks 

carbides and sigma. 

Steel Oxalic acid (10%) 24 75 3 volts Stainless Variable 

steel 

Steel 1 part nitric acid 24 75 3to 6volls Stainless 10sec Stainless (16·25-6) 

1 part glycerine steel or Bches austenite. 

3 parts hydrochloric acid carbom 

Steel 1 part nitric acid 24 75 1.5volts Stainless Up to Austenltic or ferrilec 

J partwater sleel 2min stainless. Etches 

grain boundries. 

Steel 1 part sulfuric acid 24 75 6volts Stainless 5to 15sec For Fe.Cr-NI alloys. 

1 g parts water 0.1 to 0.5 amp steel 

Steel Ammonium persuWale 24 75 6volts Stainless Attacks carbide, 

(1 Oto 100 g/1 water) 0.1 to 0.5 amp steel ferrite and austenlte 

In that order. 

Steel Sodium hydroxide 24 75 1.5 to 2 volts Stainless Colors sigma and 

(400 g/1 water) sleel carbides but not 

ferrite. 

Tantalum Sodium hydroxide (10 g/1 waler) 24 75 6volts Stainless 3to 10sec General etch. 

sleel 

Tungsten Sodium hydoxide (10%) 24 75 1.5!o 3volts Platinum 1 to5sec For tungsten and 

or stain- tungsten caJbldes. 

less steel 

Uranium 4 parts citric acid 24 75 ,,, ~· 0.01 a.mp/sq cm Stainless 10min OuUines grain 

1 part nitric acid " -~ steel boundaries 

195 parts water 

• Vanadium 1 part hydrochloric acid 24 75 310 6volts Stainless Few 

9 parts waler steel seconds 

Electromet® 4 23