Need equivalent for diode
The two triangle symbols strongly suggest that this device contains two diodes with their cathodes connected together.  Each outer pin is the anode of one of the diodes, and the center pin is the common cathodes connection.

Otherwise, the "17" and "9D" are short product codes, not full part numbers.  Even if you knew the manufacturer, you'd have to dig thru datasheets of likely parts to see which one matches this product code.

If you know something about the application and circuit these diodes are in, then you can spec a replacement.  The first parameter to know is the maximum reverse voltage the diodes would ever experience.  The current rating can't be very high just from looking at the package.  If the diodes are used as line frequency rectifiers, then any two diodes that can withstand the reverse voltage and can handle 1 A forward current should do fine.

If this is in a switching application, then reverse recovery time probably matters, and things get more complicated.