Brazing TCSPM jaw (Sept. 2016) F. Motschmann, A. Gerardin

TCSPM jaw brazing Preparation Surface treatment: Glidcop: Cu/Ni-plating CuNi: Chemical etching Filler material: SCP1 (68Ag/27Cu/5Pd), 50 µm-foil Alignment Furnace brazing

TCSPM jaw brazing Result of first brazing: Large contact areas not covered by filler material General poor wetting on CuNi-tube -> Second brazing step with added BFM at higher temperatures to exclude poor wetting by too cold piece-temperature No significant change in appearance Tube started to peel of during subsequent mounting process Practically no wetting of the CuNi-tubes all over the part Appeareance of the Glidcop-jaw in accordance with expectations

TCSPM jaw brazing Brazing Test - Evaluation Chemical Analysis CuNi (EDX, XPS) Composition indicates no detrimental species in the bulk material (Mn/Si traces?) Brazing Tests wettability Norm. mass percent (%)   Spectrum Si Mn Fe Ni Cu ------------------------------------- Tube ancien #1 0.39 0.69 1.29 9.15 88.48 Tube ancien #2 0.82 0.67 1.45 9.60 87.45 Tube nouveau #1 0.16 0.85 1.27 9.30 88.42 Tube nouveau #2 0.20 0.76 1.18 9.27 88.59 Sur plaque en cuivre OFE : 1/ Tube nouvelle livraison, non décapé, usiné une face, non rayonné 2/ Tube ancienne livraison, non décapé, surfacé P600 Sur plaque en Glidcop (cuivrage 20 µm + nickelage 7 µm) : 3/ Tube nouvelle livraison, non décapé, usiné une face, non rayonné 4/ Tube nouvelle livraison, décapé, usiné une face, rayonné 5/ Tube nouvelle livraison, décapé, usiné une face, non rayonné

TCSPM jaw brazing Brazing Test - Evaluation Brazing of current CuNi/former material: good result Brazing of etched CuNi-tube (current lot) to plated Glidcop: good result

TCSPM jaw brazing Brazing Test - Evaluation Brazing of non-etched CuNi-tube (current lot): (partially) poor wetting

TCSPM jaw brazing Cu 3 4 5 Brazing Test - Evaluation Wetting test of filler material -> wetting sufficient on every sample -> etched pieces show slightly better wettability Cu 3 4 Cu/ Cuivre OFE Sur plaque en Glidcop (cuivrage 20 µm + nickelage 7 µm) : 3/ Tube nouvelle livraison, non décapé, usiné une face, non rayonné 4/ Tube nouvelle livraison, décapé, usiné une face, rayonné 5/ Tube nouvelle livraison, décapé, usiné une face, non rayonné 5

TCSPM jaw brazing Conclusions Test brazing shows principally good results for the standard procedure (Cu/Ni-plated Glidcop, CuNi etched) Efficiency of etching process for the long tubes might have been not sufficient (other undiscovered effects that influence the surface quality of the CuNi-tube) Further approach Further etching of the CuNi-tubes before next brazing process Fast solution: Brazing with active BFM (tooling/spacers could be brazed to the structure, definitely no solution for future joining) Sophisticated solution (but maybe a bit longer): Wait for Metallurgy investigation; wetting test on real part before actual brazing