hard-facing

Japanese: hard-facing（英語表記）hardfacing

… Chemical methods include carburizing, nitriding, and sulfurizing. A method is also used in which special alloys such as cemented carbide and Stellite (an alloy of about 30% chromium, 20% tungsten, 0.1-0.3% carbon, and the remainder cobalt) are deposited on the surface of metal materials to create a surface-hardened layer, which is also called hard facing. There is also a method in which a cemented carbide such as tungsten carbide (WC) is infiltrated into the surface of steel in a reducing atmosphere at 1000-1100°C (carbide infiltration method or atomloy treatment). …

From [Thermal spraying]

…The main practical uses are rust prevention for steel materials, overlaying for machine parts, and applying heat-resistant and wear-resistant coatings. In particular, the method of spraying an alloy material that is harder than the base material for the purpose of surface hardening is called hard-facing. Aluminum spraying and zinc spraying are used for corrosion and rust prevention. …

*Some terminology explanations that mention "hard-facing" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…化学的方法としては，浸炭，窒化，浸硫などがある。金属材料の表面に超硬合金，ステライト(約30％クロム，20％タングステン，0.1～0.3％炭素，残部コバルトの合金)など，特殊合金を溶着させて表面硬化層をつくる方法もとられ，ハードフェーシングhard facingとも呼ばれる。また，鋼の表面にタングステンカーバイドWCのような超硬炭化物を1000～1100℃の還元性雰囲気中で浸透させる方法(超硬浸透法あるいはアトムロイ処理)もある。…