绝缘一般用云母片再涂上heat sink compound.

云母片：

https://www.ebay.com/itm/393327886605?var=662202692604&hash=item5b942b410d:g:CeYAAOSwfVhgodSh

Heat sink compound:

https://www.ebay.com/itm/234079276871?_trkparms=ispr%3D1&hash=item3680364f47:g:G3gAAOSw6idg5L6Z&amdata=enc%3AAQAGAAACoPYe5NmHp%252B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSRAQR8FABHjfpFoyRlXhWmYh7%252FrsgplXiUE8lxH0TIWX4uU6ZQlhqFmvLFOFkxLKapeJndhhySRLMUTMKt3Ft%252FB3ayNOqvK%252BB%252FJRBR4K5XGDKyQJfm%252FcdK%252FTNuq7Yh9x%252FqwwDlec4nqOCrMHbrw8AErpl6ABRk5TA%252BXNPp%252FP7PmcNJUQBLclUvxOiwRo0FQaFacuh1nSrR0cliU3yJwN%252FrPXighKrAnj9w7nX9bxDAyjrVpaU8GmP7HJT3Q%252BibOm%252BEb0Fh2hZ8Vzi6SnA8FPEUq1c4Kx7%252B40hlAH7%252Fh2tOWU%252FMxhGbMlvv3Z7r8IbVRmBmtU12%252FzxzefLvUC4O6zHm0LzrDYedylVIAYR%252B3xwTA6DAiElfjHEI%252B0wgx2bcvR8HXuR73Khj0mgsLRb%252BcNTdW2B36i3s4rmhvXCpe02mwrzTAABxart%252BRD2VWJO4rCIFIUmbgEzhlw7b3ESoTnULPwzmckT431kixdqA6R%252FfIH2ypV60AKkIlp4MH3fbxwTKrnHv7VajTa7GNxhUhqOjqRqcawStjk85JTJpP202yUUwJ%252Bfk78FgTFQAZb6%252FRJTGPyXyzp15ahgjV%252FV1KqnTebLF6LNhfI6Z6dFyWe%252FCHRywLK0%252BknE8SwSFHuYg8OWbxPjLbj%252FO4ew1YooLd7%252BzLr5DeYHtdU%252F%252FfXb%252BlSQT9Nx3DMl3vHtwl2u8O17ZUr2tJzToAR2XIgeZ6VKYvy3Gog%252FqWyTCD39apY1i%252FgFOAH1R5jcI9mvDxGGYyrkgx7DCfZnXSuFJOLgvhn0hGG3pFvHZWkV1jhuihS58AbEiBHMQ20grqtQaEEZjBVNV74tg0%252B4Twq4o23RIuYMiGOzwA%253D%253D%7Cclp%3A2334524%7Ctkp%3ABFBM9Jvw4p5f