Tribological Behavior of Arcing Contact Materials Based on Copper Infiltrated Tungsten Composites

Abstract

Tungsten copper composites with 70±3 wt.% W, maximum 1.5 wt.% Ni, and balance Cu were achieved as disks (diameter × height of 50×6 mm) by copper infiltration process of tungsten skeletons. Elemental analysis was assessed by WDXRF spectroscopy. Hydrostatic density was evaluated in ethanol. Vickers hardness and Young's modulus were determined in ambient air by instrumented indentation technique and Oliver&Pharr computation method. Tribological behavior was investigated under 30 N up to 400 m sliding distance and naphthenic mineral oil lubricant with a standard tribometer of ball-on-disk type. The results yielded highly dense materials with relative density over 96%, Vickers hardness (HV IT ) of 244…323, Young's modulus (E IT ) of 156…185 GPa, mean coefficient of friction of 0.11…0.22 and specific wear rate up to 8×10 -6 mm 3 /(Nm). The developed composites with low coefficient of friction and high wear resistance for use as arcing contacts in oil circuit breakers will endow high performance in service.

Graphene and its derivative reinforced tungsten–copper composites for electrical contact applications: A review

“…The major differences existent in W and Cu characteristics (Table 1) are the reasons why these composites are manufactured by various powder metallurgy (PM) techniques. Classical PM techniques include (i) pressing, sintering, and infiltration (PSI) of porous W-based skeletons with Cu-liquid phase [1][2][3][4][5][6][7][8][9][10][11] and (ii) hot pressing, and sintering (HPS) [12][13][14] that are realized at high sintering temperatures with long-duration processes of over 4 h. On the contrary, unconventional and fast PM techniques comprise spark plasma sintering (SPS) technique [1][2][3]5,[15][16][17][18] and microwave sintering (MWS) [19][20][21] at reduced sintering temperatures and much shorter duration processes (mostly of maximum 1 h) without considerable grain size growth of the sintered materials that exhibit improved properties comparatively with the materials obtained by classical PM techniques.…”

“…Among the key strategies to obtain enhanced characteristics of W-Cu-based composites was targeted the improvement of sinterability and bonding strength among W and Cu matrix through small amounts of additives like transition elements (Ni, Co, Fe, Cr, Zn, Ag, etc. ), [1][2][3][5][6][7][8]11 other metallic elements (i.e., Sn), 22 lanthanide oxides (i.e., CeO 2 , La 2 O 3 , Y 2 O 3 ) 1,18 and secondary metallic carbide phases (i.e., WC, TiC, and HfC). 9,23,24 Composites with a weight content of about 60-85% W, balance % Cu should have very good switching behavior, including high resistance to arc erosion and wear, good arc stability, high temperature, and mechanical strength, whereas high conductivities should be kept along with long lifetime in service.…”

“…Among the key strategies to obtain enhanced characteristics of W–Cu–based composites was targeted the improvement of sinterability and bonding strength among W and Cu matrix through small amounts of additives like transition elements (Ni, Co, Fe, Cr, Zn, Ag, etc. ), 1–3,5–8,11 other metallic elements (i.e., Sn), 22 lanthanide oxides (i.e., CeO 2 , La 2 O 3 , Y 2 O 3 ) 1,18 and secondary metallic carbide phases (i.e., WC, TiC, and HfC). 9,23,24…”

Synthesis and Processing Techniques of Tungsten Copper Composite Powders for Electrical Contact Materials A Review

“…On the contrary, the increase of W content in W-Cu materials results in hardness and wear resistance increase although electrical and thermal conductivity decrease. 10,11 W-Cu electrical contact materials have to meet specific requirements such as high purity, homogeneous microstructure and chemical composition, high density, low surface roughness, high hardness and mechanical strength, high electrical and thermal conductivity, high electrical breakdown strength, low contact resistance, high resistance to welding in service and high resistance to thermal and mechanical shock [12][13][14] . The addition of sintering activators (up to 1-3 wt.%) such as Ni, Fe, Co, Cr, Zn, Zr, Ag and other transition elements has advantages in improving sinterability, decreasing sintering temperature, enhancing wettability of W and Cu powder particles and improving mechanical properties of W-Cu materials but the main drawback is related to the decrease of electrical and thermal conductivity.…”