Accession Number:

AD0266381

Title:

STUDIES OF THE PARTICLE-IMPACT PROCESS FOR APPLYING CERAMIC AND CERMET COATINGS

Descriptive Note:

Corporate Author:

NATIONAL BUREAU OF STANDARDS GAITHERSBURG MD

Report Date:

1961-08-01

Pagination or Media Count:

63.0

Abstract:

A basic study was made of the particle-impact process for applying coatings of aluminum oxid with rod and po der-type flame-spraying guns. The coatings were found to consist primarily of the softer eta phase rather than the harder and more stable alpha form of alumi a. It was established that the eta phase forms because of the high quenching rates, of the order of 800,000 Csec. on a stainless steel substrate, and 34,000 Csec. on glass. Size and velocity measurements were made for particles from both gun types High-speed motion pictures showed that the powder guns sprayed particles continuously the rod gun in bursts. A chemical bond sufficient to withstand interfacial stresses without spontaneous failure was developed between the coating and smooth glass substrates, but never between the coating and smooth metal. It was shown that the apparent bond strength between the coating and iron increased exponentially with increasing roughness of an iron surface, rather than linearly.

Subject Categories:

  • Ceramics, Refractories and Glass
  • Coatings, Colorants and Finishes

Distribution Statement:

APPROVED FOR PUBLIC RELEASE