Saint-Gobain Crystal’s Milford, NH manufacturing plant produces transparent protective armor using sheets of sapphire grown from an existing crystal, according to Program Manager Russell Wooddell.
“Sapphire is second only to diamond in terms of hardness,” Wooddell said.
The crystal sheets are drawn from a pool of molten aluminum oxide and then pulled through a die to make plates that are then used in place of, or in conjunction with, glass, to produce windows and windshields that can withstand a great deal of abuse.
Saint-Gobain’s sapphire is used in aviation and in the semi-conductor and industrial market because it is able to withstand challenging conditions and is chemically inert so it won’t interact with other chemicals during various manufacturing processes.
But recently Saint-Gobain has been working with the military to improve the windows on the M142 High Mobility Artillery Rocket Launcher, beginning with the equipment used by the New Hampshire National Guard in Nashua.