Can I use aluminum wire for a 15 amp kitchen circuit?
No, and no inspector is going to sign off on it. Kitchen small appliance branch circuits fall under NEC 210.11(C)(1), which requires two or more 20 amp circuits for countertop receptacles, so a 15 amp kitchen circuit is already unusual on its own. Separate from that, solid aluminum branch circuit conductors are only manufactured and listed down to 12 AWG under Table 310.4(1), and the practical trade standard for decades has been copper only on 15 and 20 amp branch circuits. Aluminum branch wiring problems from the 1960s and 1970s, oxidation at terminations, differential thermal expansion loosening screws, and galvanic corrosion where aluminum meets copper, are why manufacturers and inspectors steer small branch circuits to copper.
Where aluminum is still allowed
Aluminum conductors are common and code compliant on feeders and services, typically 8 AWG and larger, where terminations are fewer, torque specs are followed more consistently, and devices are rated for it. Any device connected to aluminum, whether a receptacle, breaker, or wire connector, must be marked CO/ALR or otherwise listed for aluminum use per 110.14(A). Standard 15 and 20 amp duplex receptacles sold at the big box store are copper only unless the CO/ALR marking is stamped on the yoke.
If you inherit old aluminum branch wiring
Retrofitting existing aluminum branch circuits, common in some homes built before 1975, is handled with listed connection methods rather than a full rewire. AlumiConn connectors and COPALUM crimps are the accepted repair methods for pigtailing aluminum to a short copper lead at each device, which then lets you land on a standard copper-rated device. This is a repair, not new construction, and it should be documented for the homeowner and the next inspector who opens the box.
Field takeaway
Spec copper for kitchen small appliance circuits every time. If a customer has aluminum branch wiring already in the wall, pigtail with a listed connector at every device rather than trusting a bare aluminum conductor under a standard screw terminal.