I use bitcoin hardware mining. Can I modify the hardware to mine Zcash cryptocurrency or I should buy Zcash mining hardware?
ZCash uses Equihash algorithm for proof of work rather than SHA256, so if it uses ASICs, the hardware would definitely not be compatible.
No, hardware compatibility issues will rise if you try to mine ZCash on an ASIC miner. Both ZCash and bitcoin are mined using different algorithms so you cannot use the same hardware for mining.