A Logia user cannot imbue busoshoki Haki in logia form.
I have watched all the battles again and again but I could
not see any logia user using busoshoki Haki in their Logia form .
Few examples .Though the admirals were capable of using busoshoki Haki,which
they demenostrated when WB used his Gura gura to bring the platform down,It should be
noted that they were in their normal form and not logia form.
When they were in their logia form ,they did get hurt when a busoshoki user managed to
hit them.If they had imbued their logia elements with busoshoki haki ,they should not have
got hurt in the first place.
Eg,When Akoji was trying to freeze WB ,kozu intervened and broke Akoji in iceform,Akoji did spit blood after that .If akoji had used busoshoki haki,then his ice form should had become as hard as diamond atleast theoritically and should not have been broken very easily.
Remember the chapter when luffy and gang had to face Akoji.
Luffy's hit broke his ice form very easily though he did not get hurt because his logia abilities.
When Marco and kozu attacked akainu's subtle lava ,even he got hurt .Why could not he imbue bushoshoki haki over his lava element .
Same when kizaru vs Marco,Kizaru vs Rayliegh ,Kizaru was in his logia form but he could used busoshoki haki around his logia form and not got hurt.
I have watched all the battles again and again but I could
not see any logia user using busoshoki Haki in their Logia form .
Few examples .Though the admirals were capable of using busoshoki Haki,which
they demenostrated when WB used his Gura gura to bring the platform down,It should be
noted that they were in their normal form and not logia form.
When they were in their logia form ,they did get hurt when a busoshoki user managed to
hit them.If they had imbued their logia elements with busoshoki haki ,they should not have
got hurt in the first place.
Eg,When Akoji was trying to freeze WB ,kozu intervened and broke Akoji in iceform,Akoji did spit blood after that .If akoji had used busoshoki haki,then his ice form should had become as hard as diamond atleast theoritically and should not have been broken very easily.
Remember the chapter when luffy and gang had to face Akoji.
Luffy's hit broke his ice form very easily though he did not get hurt because his logia abilities.
When Marco and kozu attacked akainu's subtle lava ,even he got hurt .Why could not he imbue bushoshoki haki over his lava element .
Same when kizaru vs Marco,Kizaru vs Rayliegh ,Kizaru was in his logia form but he could used busoshoki haki around his logia form and not got hurt.