THERMAL SPRAY COATING AND COMPOSITE THERMAL SPRAYING MATERIAL

• Main Authors: YASUDA TSUJIHIKO, HANNOU AKIYOSHI
• Format: Patent
• Language: English
• Published: 28.08.2002
• Edition: 7
• Subjects: CASTING; CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; FOUNDRY MOULDING; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; PERFORMING OPERATIONS; POWDER METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TRANSPORTING

PROBLEM TO BE SOLVED: To provide a thermal spray coating which is not eroded even when repeatedly used, and has durability (an elongated life) in molten metal. SOLUTION: The thermal spray coating is obtained by successively depositing first to third thermal spraying layers on the substrate to be protected. The first thermal spraying layer is formed of a heat resistant alloy having a thermal expansion coefficient close to that of the substrate to be protected. The second thermal spraying layer has a composition containing, by mass, about 30 to 70% molybdenum boride (MoB), about 20 to 40% nickel(Ni) or cobalt(Co), about 5 to 20% chromium(Cr), and about 5 to 10% metallic boride of at least one kind selected from Cr, W, Zr, Ni and Nb. The third thermal spraying layer has a composition containing about 25 to 75% ceramic powder which has nonwettability to molten light metal and about 75 to 25% molybdenum boride(MoB) powder.