Abstract Process for producing sheet metal substrates having high corrosion and erosion resistance to hot exhaust gases of internal combustion engines by A. melt spraying a coating about 125-250 microns thick of a mixture of about 70-90 weight percent nickel and about 10-30 weight percent aluminum on sheet metal substrates of a chromiumiron alloy having, by weight, 10-40 percent chromium, 0-40 percent nickel, o-10 percent manganese, 0-6 percent aluminum and 35-80 percent iron, the chromium, nickel, manganese, aluminum and iron content totaling at least 95 percent, and B. diffusion coating the nickel-aluminum coating with aluminum to a thickness of at least 25 microns; and Exhaust manifold reactor inner chambers having at least the surfaces which deflect the initial exhaust gas impingement from internal combustion engines treated by the above coating process.
The process of claim 1 wherein said chromium-iron alloy consists essentially of, by weight, 15-25 percent chromium, 28-36 percent nickel, 0.25-2.0 percent manganese, 0-2.0 percent aluminum and 40-55 percent iron.
Claim 2
Dependent Claim
14 words
The process of claim 2 wherein said aluminum diffusion coating is 25-50 microns thick.
Claim 3
Dependent Claim
21 words
The process of claim 3 wherein the melt spraying in (A) consists of flame-spraying the molten nickel-aluminum from a flame-spray gun.
Claim 4
Dependent Claim
22 words
The process of claim 3 wherein the melt spraying in (A) consists of plasma jet-spraying the molten nickel-aluminum from a plasma gun.
Claim 5
Dependent Claim
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The process of claim 3 wherein the sheet metal substrates comprise the surfaces of an exhaust manifold reactor inner chamber which deflect the initial exhaust gas impingement from an internal combustion engine.
Claim 6
Dependent Claim
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The process of claim 3 wherein the chromium-iron alloy consists essentially of, by weight, 46 percent iron, 32 percent nickel, 20.5 percent chromium, 0.04 percent carbon, 0.30 percent titanium, 0.75 percent manganese, 0.35 percent silicon.