The　radiative　energy　loss　accounts　for　roughly　70%　of　the　energy　loss　in　the　polysilicon　chemical　vapor　deposition　(CVD)　reactors　and　therefore　takes　up　to　about　25%　cost　in　the　production　of　polysilicon　used　for　solar　cells.　In　this　work,　cold　spray　(CS)　process　was　used　to　deposit　Ag　coating　with　ultra-high　infrared　reflectance　on　inner　wall　of　the　CVD　reactor　to　minimize　the　radiative　losses.　To　solve　the　bond　strength　problem　of　depositing　soft　coatings　on　hard　substrate　by　CS,　a　Ni　buffer　layer　with　medium　hardness　was　introduced.　Results　show　that　Ag　coating　can　be　successfully　deposited　with　a　porosity　lower　than　0.1%.　Even　the　as-sprayed　Ag　coating　has　a　high　near-infrared　reflectivity　of　92%　which　was　much　higher　than　that　of　a　well-polished　substrate　surface　(65%)　suggesting　an　excellent　radiation　energy　saving　capacity.　The　bond　strength　of　the　Ag　coating　is　significantly　increased　from　3.7　MPa　to　35.4　MPa　and　the　thermal　shock　resistance　is　improved　from　22　±　3　to　over　150　cycles　by　the　Ni　buffer　layer.　The　scientific　methodology　demonstrated　here　can　be　a　cost　effective　approach　to　reduce　the　radiation　energy　losses　in　the　polysilicon-CVD　industry.　©　2021