METHOD FOR HARDENING PLATINUM OR PLATINUM ALLOY AND METHOD FOR HARDENING PALLADIUM OR PALLADIUM ALLOY

摘要

PURPOSE: To impart high hardness to the surface of Pt or Pt alloy without roughening the surface. ;CONSTITUTION: A mixture of 40% B₄C with 20% borax (Na₂B₄O₇) is prepd., 20% NaCl and 20% KCl are added to the mixture and they are mixed in a crucible. Platinum of 99.95% purity cast into a hexagonal-round ring is put in the resultant mixture and heated at 800°C for 4hr in an electric furnace. Boron in the mixture penetrates into the surface of the Pt ring to harden the surface. The Vickers hardness Hv of the surface of the Pt ring is 350. The surface of the hardened ring is hardly roughened and is comparable to the surface of an unhardened Pt ring.;COPYRIGHT: (C)1996,JPO