I've heard the same info about metal particles being added to the ceramic mix for metal detector functioning as well.
I also do not know if this is true or not but, I do know that some ceramics do have a component of metal as part of its makeup. Don't know which ones but, some do.
So far all these knives have performed well and have stood up to the other users who don't quite know how to handle a ceramic knife. dropping them into the drawers instead of the knife block, dropping them on the counter top, tossing them loosely into the dishwasher on the top rack where they fall to the bottom, etc.
Fortunately, they're inexpensive so I can get a replacement easily enough if i need to.

I have read where certain states had banned the sale of ceramic knives because a person might sneak one by a metal detector. The govmt made a manufacturing requirement to add some ferros material to the ceramics to sound the metal detecting alarm. Don't know for sure if that is true. I have a ceramic window ice scraper that I bought 14 years ago and it has held up good.

I went back and bought the 3" paring knife to use when I begin to preserve fruits this season, I've gotten a hankering for some strawberry jam. :D
I decided to buy the paring knife to help with cutting up the strawberries and to give it a go and try it out.
It's turned into one of the favorite knives in our house too. Always sharp and cuts everything, easy to use and to clean.
My mother-in-law liked that one so well that she asked me to get her the 5" utility knife for her to cut tomatoes and other items. I did and she is very happy with it.
I give a hearty endorsement to the Harbor Freight ceramic knives, you won't be disappointed!

I've been looking at ceramic knives for some time now, actually since they first became available to consumers, and finally decided to give one a try out. What kept me from buying one all this time was mostly cost, these things are expensive!
I had seen three different ceramic knives at Harbor Freight for my last several visits and I gave in and bought the 6" chef's knife.
I am very impressed with this cheap ceramic knife! I have only had it for three months now and use it quite a bit and it has not even begun to think about getting dull, has not yet chipped, cracked or broken and slices food stuffs so much easier than even my best steel knives.
There are three varieties at Harbor Freight, a paring knife, a utility knife and the chef's knife. I'm going to purchase the two I don't have when I can to have a complete set. I like these knives and the price can't be beat!
You can see them here:

http://search.harborfreight.com/cpisearch/web/search.do?keyword=ceramic+knives&Submit=Go

If you're crazy like I am, get one and try it out, I do believe you will like these knives too.


Also, even if they get dull, doubtful, they can be sharpened on a fine or medium whetstone with water for the surface lube. Don't use oil, it won't help and sharpen them deliberately but gently and take your time.