Because of its very high melting point, hafnia is also used as a refractory material in the insulation of such devices as thermocouples, where it can operate at temperatures up to 2500 °C.
bɪkˈʌz ʌv ɪts vˈɛɹi hˈaɪ mˈɛltɪŋ pˈɔɪnt, hˈæfniə ɪz ˈɔːlsoʊ jˈuːzd æz ɐ ɹᵻfɹˈæktɚɹi mətˈɪɹiəl ɪnðɪ ˌɪnsəlˈeɪʃən ʌv sˈʌtʃ dɪvˈaɪsᵻz æz θˈɜːməkˌʌpəlz, wˌɛɹ ɪt kæn ˈɑːpɚɹˌeɪt æt tˈɛmpɹɪtʃɚz ˌʌp tə tˈuː θˈaʊzənd fˈaɪvhˈʌndɹɪd dᵻɡɹˈiːz sˈiː.