Heat sink- strange app.

Question

A cousin called me the other day with an interesting problem.  A wafer of nichrome-like metal is fused onto a substrate with a spot-welding type process using 400 volts and produces a lot of localized heat, 1,000 F., that they need to sink away quickly.  The problem is that the heat sink must be non-conductive to electricity but pull heat well.  I suggested silipads but he said they tried that and they vaporize.  Any ideas?