PROCESS FOR ADHERING AN OXIDE COATING ON A COBALT- ENRICHED ZONE, AND ARTICLES MADE FROM SAID PROCESS

摘要

IMPROVED PROCESS FOR ADHERING AN OXIDE COATING ON A COBALT-ENRICHED ZONE, AND ARTICLES MADE FROM SAID PROCESS An improved fabrication process for cobalt-enriched cemented carbide substrates is disclosed, in which an article is generally comprised of tungsten carbide, cobalt, and carbides, nitrides or carbonitrides of titanium, tantalum, and niobium, or mixtures thereof. In one aspect of the invention the article is contacted with nitrogen gas and then sintered in the absence of nitrogen gas to form a cobalt-enriched, B-1 phase-depleted zone. The article is then sintered in nitrogen gas to form a B-1 phase enriched layer on the surface of the article. Additionally, a metal oxide wear layer can be provided on the article.