Copper has excellent thermal conductivity, which explains its widespread use in household implements such as pots and pans. The next most conductive elements are gold, silver and then aluminium.
Adding nickel to copper reduces its thermal conductivity, which continues to fall as the nickel content increases. The thermal conductivity of Hiduron® 130 (DTD 900/4805, 2.1504) is c. 46 (W/m.K), whereas it is only c. 17.5 (W/m.K) for Alloy 500 (UNS N05500, 2.4375, BS3076 NA18, Monel® 500), which is mostly nickel alloyed with copper, rather than mostly copper alloyed with nickel.