A part include a refractory alloy including a niobium matrix having metal silicide inclusions present therein, the surface of the part being coated by a protective coating, the protective coating including a phase having the following stoichiometry: (Nb.sub.xTi.sub.1-x).sub.3M.sub.Cr.sub.Si.sub.X.sub. where M designates Fe, Co, or Ni, X designates one or more other elements that might be present, x lies in the range 0 to 1, x lies in the range 5 to 8.5, and the sum + lies in the range 3 to 7; or Nb.sub.4M.sub.Si.sub.X.sub. where M designates Fe, Co, or Ni, X designates one or more other elements that might be present, lies in the range 3.2 to 4.8, and lies in the range 6 to 8.

A part include a refractory alloy including a niobium matrix having metal silicide inclusions present therein, the surface of the part being coated by a protective coating, the protective coating including a phase having the following stoichiometry: (Nb.sub.xTi.sub.1-x).sub.3M.sub.Cr.sub.Si.sub.X.sub. where M designates Fe, Co, or Ni, X designates one or more other elements that might be present, x lies in the range 0 to 1, x lies in the range 5 to 8.5, and the sum + lies in the range 3 to 7; or Nb.sub.4M.sub.Si.sub.X.sub. where M designates Fe, Co, or Ni, X designates one or more other elements that might be present, lies in the range 3.2 to 4.8, and lies in the range 6 to 8.

A method of applying a protective coating to an article comprises the steps of a) depositing aluminum in a surface region of an article, and b) depositing chromium is the surface region of the article subsequent to step a), whereby at least a portion of the chromium replaces at least a portion of the aluminum. Another method and an article are also disclosed.

A method of applying a protective coating to an article comprises the steps of a) depositing aluminum in a surface region of an article, and b) depositing chromium is the surface region of the article subsequent to step a), whereby at least a portion of the chromium replaces at least a portion of the aluminum. Another method and an article are also disclosed.

The invention relates to a method of providing a metallic surface with a protective diffusion layer, wherein a chromium-containing slip is applied to the surface and is then subjected to a heat treatment in order to produce the protective diffusion layer. In addition to the chromium powder, the slip contains silicon powder in order to shorten the hold time required in the heat treatment.

The invention relates to a method for producing a nickel aluminide coating on a metal substrate. The method includes the following steps: a) coating the substrate with a nickel deposit; b) applying an aluminum sheet onto the nickel deposit from step a) so as to form an assembly made up of the substrate coated with the nickel deposit and the aluminum sheet; and c) subjecting said assembly to heat treatment at a temperature that is lower than the melting point of aluminum, and at a low pressure so as to induce a reaction between the aluminum and the nickel and thus form a -NiAl nickel aluminide layer mounted on a nickel layer. The invention is particularly of use for protecting the materials used in turbines of aircraft engines.

A method of applying a protective coating to an article comprises the steps of a) depositing aluminum in a surface region of an article, and b) depositing chromium is the surface region of the article subsequent to step a), whereby at least a portion of the chromium replaces at least a portion of the aluminum. Another method and an article are also disclosed.

A method of applying a protective coating to an article comprises the steps of a) depositing aluminum in a surface region of an article, and b) depositing chromium is the surface region of the article subsequent to step a), whereby at least a portion of the chromium replaces at least a portion of the aluminum. Another method and an article are also disclosed.

A steel member with surface modified during manufacture has good anti-corrosion properties. The steel member includes a steel substrate, a metallic diffusion layer formed on the steel substrate, and an alloy deposition layer formed on the metallic diffusion layer. The steel substrate is made of medium-carbon steel or medium-carbon alloy steel. After cleaning and heating processes are applied, the metallic diffusion layer includes pearlite and ferrite crystals and hardness of the surface is also enhanced. The alloy deposition layer includes zinc ferrum alloy. The metallic diffusion layer and the alloy deposition layer have a total Micro Vickers Hardness in a range from 240 to 500.

A steel member with surface modified during manufacture has good anti-corrosion properties. The steel member includes a steel substrate, a metallic diffusion layer formed on the steel substrate, and an alloy deposition layer formed on the metallic diffusion layer. The steel substrate is made of medium-carbon steel or medium-carbon alloy steel. After cleaning and heating processes are applied, the metallic diffusion layer includes pearlite and ferrite crystals and hardness of the surface is also enhanced. The alloy deposition layer includes zinc ferrum alloy. The metallic diffusion layer and the alloy deposition layer have a total Micro Vickers Hardness in a range from 240 to 500.