The present disclosure provides a high-strength thermally insulating partition assembly (e.g., muffler plate) for use in a scroll compressor. The assembly includes at least one metal plate and an insulating region. The insulating region may have at least one insulating material or may be a low-pressure or vacuum chamber. The partition assembly serves to minimize heat transfer between a low-pressure refrigerant on the low-pressure suction side and a high-pressure high-temperature refrigerant on the high-pressure discharge side of the compressor. The insulating region may be sandwiched between multiple metal plates. The insulating region may be coated on the metal plate. The insulating region may also be a preformed component or mask that is coupled to the metal plate via a mechanical interlock system.