Metco 405 10-008

Metco® 405 Nickel Aluminide Wire

Technical Bulletin #10-008

Issued October 2000Supersedes May 1970

TM

#10-008 2Metco 405 Nickel Aluminide Wire

Metco 405 Nickel Aluminide Wire was especially developed to be a better self-bonding material thanmolybdenum wire, particularly with regard to bond strength. In addition, it has many applications as asingle coat system where dense coatings, resistant to oxidation, high temperatures and temperaturechanges, are required.

Metco 405 Wire is chemically similar to Metco 404 Nickel Aluminide Powder and, like 404, undergoesan exothermic reaction during spraying. Also, like 404, it produces coatings which are dense andresistant to oxidation, high temperatures and temperature changes.

The exothermic reaction of Metco 405 Wire derives from its chemical composition. When the wirereaches a certain temperature in the spray gun flame, the nickel and aluminum react to form nickelaluminide and evolve a great deal of heat. It is thought that the extra heat provided to the moltenparticles by the exothermic reaction, coupled with the high particle velocity of the Metco metallizingprocess, account of the self-bonding characteristics of the coating and its exceptional strength, bothperpendicular and parallel to the substrate.

Metco 405 Wire can be sprayed with most Metco Flame Spray Guns. It cannot be sprayed with theMetco Types 5E and 7E Guns, since these high-speed units cannot be slowed down to the 21/2 - 31/2

feet-per-minute feed rate required. Whenever a Type KT or Type XT Extension is used, a specialangular air cap, Cat. No. KT 6-1/8T or XT 6-1/8T, is required.

Metco 405 Wire was developed to replace Sprabond Wire for bonding. It is better than Sprabond; itprovides the user with better coatings at lower cost.

Coatings sprayed with 405 show bond strengths up to 4230 psi, as compared with a little more than2000 psi for coatings of Sprabond.

Nickel 80%Aluminum 20%

Coating texture, as-sprayed: CoarseTensile strength: 18,000 psi(perpendicular to the direction of spraying)

Metco® 405 Nickel Aluminide Wire

Equipment

Applications

Typical Composition

Physical Properties

Typical hardness: Rc 22Coatings of Metco 405 Wire are considerably harder than coatings of Metco 404 Powder. This is because the nickel aluminide phasecontained in the wire coating is almost exclusively the harder NiAl, whereas the powder coating contains about as much (35 - 40%) of the relatively soft Ni3A1 as it does of the hard NiA1.

Density: 6.0

Wear resistance: Laboratory tests indicate that coatings of Metco 405 Wire are equivalent in wear resistance to coatings of Sprabond Wire, but are not equivalent in anti-galling properties.

Corrosion resistance: Not recommended for corrosion resistance in aqueous solutions of acidic, basic or neutral salts.

Tensile Strength of Bond vs. Overcoat Material(SAE 1020 Substrate)Overcoat Material Bonding Material

Sprabond Wire Metco 405 WireHandbook Values - psi Average psi - (5 tests)

Sprasteel 10 2150 3150Sprasteel LS —— 3060

Metcoloy #1 2250 2775Metco Aluminum 1640 2230

Metco SF Aluminum 2050 2550Metco 201 Powder —— 1380

Tensile Strength of Bond vs. SubstratesBond Strength - Average psi - (5 tests)

Substrate (Metcoloy #2 Overcoat)

Hardened Die Steel 2950AISI 302 3050SAE 1113 3400

Titanium 3150Nitrided Steel 2790

The best way to describe the performance of 405 as a bond coat material is by saying that it is atleast equal to 404 applied with a ThermoSpray Gun. Tests show an average tensile bond strength of3000 psi, with a range of 2000 - 4000 psi. The highest figure obtained in test on a ground substrate


Bonding Data

The internal strength of 405 coatings is higher than Sprabond coatings, parallel to the base material,as well as perpendicular to it. In the past, Sprabond Wire has always been the weakest element in acomposite base-plus-Sprabond-plus-top coat system. With 405 this is not the case. Here, thedifference in strength is of the order of about 18,000 psi versus approximately 7,5000 psi.

The bond is subsequent coating materials is better with 405 than with Sprabond. This is especiallytrue with top coats of Sprababbitt A, which require a rough surface for best bond. The texture of 405coatings is generally coarser than normally applied coatings of Sprabond. Considerable skill andexperience is required to produce a Sprabond coating coarse enough to permit good bond withbabbitt, so much so that many operators apply a coat of Metcoloy between the Sprabond and theSprababbitt A to provide a rougher surface. None of this is necessary to assure a good bond between405 and subsequent coats.

Metco 405 is easier to apply, since it requires less precise control of coating thickness. The advantageof 405 is that if the coating runs a little thicker, say up to .006”, the finished job will be stronger,whereas every thousandth of Sprabond over the recommended maximum thickness tends to makethe finished job weaker, since the Sprabond itself is weaker.

A major advantage of 405 over Sprabond is the fact that strong, sound, reliable and reproduciblecoatings can be sprayed without dependence on technique. For instance, nozzle-to-work distanceshould be kept between 5 - 6" with 1/8" Sprabond, but good bond strength results when nozzle-to-workdistance is anywhere between 2 - 8" with 405. The wire feed with Sprabond must be very slow, but405 is sprayed at about the same speed as the Sprasteels. Gas flows and air pressure are not criticalfor the successful spraying of 405: they are critical with Sprabond.

Metco 405 is considerably more versatile than Sprabond. For one thing it can be sprayed withpropane, while Sprabond cannot. Metco 405 will bond reliably to base materials such as nitrided steel,to which Sprabond does not bond. In general 405 bonds to all materials to which 404 Powder willbond.

It will self-bond satisfactorily to ground surfaces of the following materials:

Low Carbon Steels — SAE 1020, SAE 1113Hardened Die Steel — Oilgraph (Rc 58)Stainless Steel — AISI Type 302Nitrided Steel — Nitralloy GTitanium — UnalloyedCast Iron — ASTM A48-56

Reliable self-bonding of Metco 405 Wire has not been achieved on copper, molybdenum, tantalum,columbium or tungsten. Self-bonding tensile strengths somewhat lower than normal for Metco 405, butstill considered to be reliable, were obtained on aluminum, brass and Kovar. Considerable experiencesince the release of Metco 404 Powder has indicated that both Metco 404 Powder and Metco 405Wire behave similarly when sprayed on aluminum substrates.



Metco 405 coatings are rough and readily lend themselves to subsequent coats of other materials.The following representative materials have been successfully applied to coatings of Metco 405:

Metcoloy #1 Metco SF AluminumSprabronze AA Metco 201Sprasteel 10 Metco AluminumMetcoloy #2 Sprasteel LS

Metco 405 cannot be used under fused hard-facing alloys.

Metallographic examination of Metco 405 coatings show that the self-bonding phenomenon is due to adiscontinuous thin alloy or diffusion layer. The bond of the subsequent layers is due to the normalphysical mechanisms.

All substrate cleaning procedures used for Sprabond Wire bonding are necessary for Metco 405 Wire.Severe substrate oxidation should be removed. The substrate should be preheated to prevent theformation of condensate. The best bond is obtained if the bonding coat is applied in one pass.

Metco 405 comes level wound on a disposable reel, which is further packaged in a corrugated carton.This package offers sufficient protection for the wire during shipping and general handling. However,when the wire itself is handled, as in spraying, care must be taken not to sharply bend or kink it. Thismay cause internal damage (some external damage may also occur) which, in most cases, results inthe wire spitting during spraying. Special rear wire guides, to prevent sharp bending of the wire, areavailable.

Because of the bright flame, eye protection should always be worn when spraying Metco 405 Wire.

Lighting Flow Meter ConsumptionAir Air Pressure Readings Oxy. Fuel

Fuel Wire Cap Pres. Fuel Fuel Metal Cu. GasGun Gas Size+ Size Psi Oxy. Gas Oxy. Gas Air Lbs. Ft. Cu. Ft.4E Acet 1/8" H 65 41 12 34 29 49 5 75 27

Prop 1/8" H 55 35 30 49 20 45 5 107 19MAPP 1/8" H 55 40 35 40 23 46 5 89 23

8E Acet 1/8" C* 65 26 8 46 33 49 5 90 29Prop 1/8" C* 55 43 35 68 30 47 5 170 30MAPP 1/8" C* 55 41 39 69 30 46 5 170 31

K Acet 1/8" C 60 38 12 42 34 45 5 92 32Prop 1/8" D 50 46 37 62 28 38 5 155 28MAPP 1/8" D 50 40 40 59 31 38 5 146 32

Y Acet 1/8" C 65 42 15 48 39 61 5 112 41Prop 1/8" D 60 40 37 69 29 59 5 169 29MAPP 1/8" D 60 65 33 5

Spraying

*Do not use the “EC” Air Cap.+Use special rear wire guide Cat. No. 8E 162 when using Metco 4E and 8E Guns.

NOTE: Use adapter fittings for MAPP and Propane Gases.

Recommended bond coat thickness for optimum bond: .004 - .006".

Approximate Deposit Efficiency: 75%

Coverage: 119 sq.ft./hour .001" thick.

Wire Required: .042 lbs/sq.ft./.001" thick.

Coating Weight: .0312 lbs/sq.ft./.001" thick.

Spraying Distance:The spraying distance should be from 4 - 6" for the best results. The spraying distance is not ascritical with Metco 405 Wire as it is with Metco 404 Powder. Good bond strengths have been achievedat 2" as well as 8".

Wire Spraying Speed:3 ± 1/2 ft/min. is recommended. This rate is slightly lower than that for 1/8" diameter Sprasteel andMetcoloy Wires.

At three feet per minute the position of the molten rounded tip is back in the air cap approximately 1/16"and does not change substantially within the given speed range.

NOTE: Because of the vivid glow caused by the exothermic reaction, colored goggles must be worn tobe able to see the wire tip and adjust the speed correctly.

An easy way to adjust for proper spraying speed, without measuring the feed rate per minute, is tobring the molten tip even with the front of the air cap and then back off about ten clicks on the speedcontrol ring.

Metco 405 is considerably more convenient to handle than Sprabond, since it is so much less stiff andspringy. This makes it much easier to handle on the wire control unit, and much easier to manipulatethe gun while spraying into corners.

As far as cost savings are concerned, one of the biggest cost factors known is job failure, whichusually means bond failure. Metco 405 reduces the chance of bond failure to the absolute minimum.

Another item of cost in connection with Sprabond arises from the common practice of cutting three orfour foot lengths of wire off the coil. This is done for ease of handling, since Sprabond is so stiff andhard to handle. The practice results in a lot of unusable wire ends which can only be thrown away.This cost is completely eliminated by 405, which is pliable and easy to handle.

Metco 405 is less expensive to use since it sprays at normal steel wire speeds, with no time or wirewasted adjusting to a slow speed for the bond coat and then speeding up the gun to spray the top



coat - and with a savings also in wear and tear on the gun speed control parts.

Another cost savings lies in the greater ease of handling and storing, resulting from the comparativelightness of 405. For instance, five pounds of 1/8" 405 is the same length as ten pounds of 1/8"Sprabond, and the coating produced is lighter too, by about 20%.

There is no tendency for spontaneous initiation of the exothermic reaction. Precautions should betaken when starting to spray Metco 405 Wire. Any excess tip that flies off remains red hot slightlylonger than usual. It may be a potential fire hazard.

The information provided in this document is for the convenience of Sulzer Metco’s customers for thepurpose of evaluation and proper use of the Sulzer Metco product(s) described herein. This documentand the information contained herein is the property of Sulzer Metco and shall not be used, disclosed,or reproduced in whole or in part for any purpose other than for the use of said product(s). Nor shallthis information be used in any way with goods not manufactured and sold by Sulzer Metco. SulzerMetco makes no warranties, express or implied, as to the information contained herein.

Precautions

Documents

Metco 405 10-008