What were US 1945 silver coins?

Nickels contained about 1/3 silver by weight during the years 1942-45, because nickel was needed for the war effort.

Dimes, quarters, and halves were made of 90% silver, 10% copper.

Cents were copper; they've NEVER been struck in silver regardless of any rumors.

Dollar coins weren't minted in 1945. Those in circulation from 1935 and earlier were the same metal composition as dimes, quarters, and halves.