Either Hard or soft solders may contain some Silver. in all the machine shops I worked in over the years "Silver Solder" was used to refer to the Hard variety. This solder melts at temperatures at least twice, & generally more ,than soft solders. It is generally though a lower temperature than Brazing. A favorite in the shop I spent the most time in was known as Ezy-Flow 45 which melted at around 1145°F.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra