
1) Refractory metal
Found on
https://www.crosswordclues.com/clue/brightray

Brightray is a nickel-chromium alloy that is noted for its resistance to erosion by gas flow at high temperatures. It was used for hard-facing the exhaust valve heads and seats of petrol engines, particularly aircraft engines from the 1930s onwards. It was developed by Henry Wiggin and Co at Birmingham. As well as its use as a coating, it is also ...
Found on
http://en.wikipedia.org/wiki/Brightray
No exact match found.