WEAR-RESISTANCE OF BRONZE-BONDED SAMPLES OF DIAMOND TUBULAR DRILLS PROVIDED WITH ULTRAFINE DIAMOND AND MOLYBDENUM POWDERS

Abstract

The paper examines the abrasive wear rate of samples produced by vacuum impregnation of ultrafine diamond (ACM 1/0) and molybdenum powders with tin bronze. The tests are conducted using a SiC-based abrasive wheel in the presence of cooling water. The introduction and increase of the ultrafine diamond powder in the samples substantially decreases their wear rate (by a factor of 78). The hardness of the samples first increases when diamond powder content increases to 5 wt.% and then decreases when ACM 1/0 content further rises to 11 wt.% because of small porosity that appears in the samples. The use of bronze binder containing more than 15 wt.% tin does not decrease the wear rate of the test samples and, hence, of the associated diamond tool, in spite of increase in its hardness.