Best type of flat iron for Natural hair

Do titanium flat irons get the hair straighter than ceramic irons?  Should I use one on my Afro curly hair?

YES, they do get the hair straighter than ceramic flat irons. They have higher amounts of heat. 

NO! 
Not if your goal is to keep your hair healthy and wear it natural the majority of the time. 

Yes! 
If your goal is to be a straight hair natural. You are natural but you desire to wear your hair heat straightened most of the time. Titanium flat irons give you a much silkier, smoother finish than a ceramic flat iron. Expect your hair to come out straighter and require fewer passes. Choose a flat iron which has a digital heat setting so you know what temperature you are using. 

The chances of heat damage are greater with titanium plates. Keep that in mind if you choose one. 

Here are some top consumer rated titanium flat irons:
Top Titanium flat iron
Babyliss PRO Nano 
Croc 1.5'
Theorie SAGA 1' 
Babyliss Pro Nano Ultra Thin 1'
HAI Convertable 1.25'