A process of converting an outer layer of an object made of a refractory metal, such as titanium, into a carbide of the refractory metal. A molten metal, such as molten lithium, is placed adjacent the outer surface of the object. The lithium does not react with the titanium, nor is it soluble within the titanium to any significant extent at the temperatures involved. The molten lithium contains elemental carbon, that is, free carbon atoms. At high temperature, the carbon diffuses into the titanium, and reacts with titanium atoms to form titanium carbide in an outer layer. Significantly, no other atoms are present, such as hydrogen or oxygen, which can cause problems, because they are blocked by the molten lithium.

A process includes applying a slurry to a surface of a metallic article to produce a slurry film on the surface. The slurry is composed of a liquid carrier, chromium and aluminum, and an agent that is reactive with the chromium and aluminum to form intermediary compounds. The article and slurry film are then thermally treated at an activation temperature at which the agent reacts with the chromium and aluminum to form the intermediary compounds. The intermediary compounds deposit the chromium and aluminum on the surface. The thermal treating also diffuses the chromium and aluminum into a sub-surface region of the article such that the sub-surface region becomes enriched with chromium and aluminum.

A process includes applying a slurry to a surface of a metallic article to produce a slurry film on the surface. The slurry is composed of a liquid carrier, chromium and aluminum, and an agent that is reactive with the chromium and aluminum to form intermediary compounds. The article and slurry film are then thermally treated at an activation temperature at which the agent reacts with the chromium and aluminum to form the intermediary compounds. The intermediary compounds deposit the chromium and aluminum on the surface. The thermal treating also diffuses the chromium and aluminum into a sub-surface region of the article such that the sub-surface region becomes enriched with chromium and aluminum.